Loose Threads:

If Daria is trying to impress Trent so much (Jane: Oh-la-la, is that lipstick? Daria: I just had a lollipop.) why doesn't she use those fake boobs she got in "Too Cute"?

Why does Jane go all the way to Daria's house to meet Trent when she lives with him?

Why doesn't the drummer come along to Alternapalooza? It's his van.

Where did Jane learn enough about cars to be able to fix one with a glue-gun?

Is something going on between Jane and Jesse, or does she just look so happy because she got Daria comfortable around Trent?

Notables:

We get to hear Trent playing his guitar and singing for the first time (and the singing is done by the usual voice-actor, not by a stand-in).

Trent seems very ready to change his band's name at Daria's suggestion. This may be a play on the old Monty Python skit, "Rock Notes".

Alternapalooza is a play on the name Lolapalooza (although I doubt I need to point this out to this audience).

Sandi has the Fashion Club well under her control in this episode.

Jake blows up at Quinn when she mentions thinking about getting her navel pierced, something Daria does is season two.

The famous Sixties rock festival Jake attended - Altamont - was famous because the Hell's Angels (who had been hired as security) killed some concertgoers.

Jake says "And stay away from the brown-", which is a Woodstock reference. On the loudspeaker at the Woodstock festival, someone said "stay away from the brown acid. It's not poison, it's just bad acid."

Jake mentions washing the cars (plural). This is the second time we've heard about another vehicle, but we've still only see the car Jake drives.

The license plate on the van is 12 NU. I've never seen a non-custom plate with that few letters, so I wonder what it stands for.
One too new? One, two 'n you?

Kevin drives a red Jeep with a long whip antenna, and it looks like Jamie is the one first driving the convertible, although Sandi takes over later.

The guy in the toll booth is Curtis Stelano, one of Trent and Jesse's old classmates.

The big sign they drive by says "Pickfair Commons: if you lived here, you'd be home by now"

If the windows on the van can't open, how does the bee get in? Also, how does Jesse have his arm hanging out the window with breeze in his hair (during the "Everybody Hurts" scene)?

The tape on the steering wheel, when shown from the side, looks like it might contain some initials.

Daria really isn't comfortable in the wilderness... (Daria: Stop staring at me, you squirrel pervert!)

Daria's comment about "I'm ready for my abuse, Mr. DeMille" is a parody of Norma Desmond in Sunset Boulevard. The line is usually quoted as "I'm ready for my close-up, Mr. DeMille." but I think the original was "And now, Mr. DeMille, I'm ready for my close-up."
The film has some very dark humor in it, and tends to make fun of the Hollywood scene (of the time, but it hasn't changed all that much). In addition, the character Daria quotes (Norma) becomes insanely jealous of her love interest (Joe Gillis), who attempts to walk out on her.

An open D tuning is, in order from the fattest string, D-A-D-F#-A-D which is opposed to a regular tuning of E-A-D-G-B-E.

Helpful Corn could be a reference to Korn.

Trent got his tattoo out of a magazine.

Mistakes:

When Daria and Jane walk down to the basement to complain about the noise Trent is making with his guitar Jane is wearing black tights. Before she tells Trent to turn it down she is standing there with no tights, bare legged, later she is wearing the tights again.

Daria's lipstick disappears as she gets into the van, maybe it was just a lollipop.

The road to Alternapalooza changes from a two-lane highway to four-lane highway and then back to a two-lane highway.
If lawdale is in CT (or any new england state) then these are not mistakes: The road to Alternapalooza changes from a two-lane highway to four-lane highway and then back to a two-lane highway. This happens a lot in CT. The road I took to go to college from home went from a 3 lane on both sides to a regular one-lane-each-way-with-stoplights road. Highways in CT are not big and they often turn into regular roads (many "freeway ends 500 ft" signs). They often go from 4 to 2 lanes and back especially when entering or exiting larger cities.
- angelinhel

There's a tractor on the highway in the traffic-jam, right in front of the Tank, but it's gone after the "Everybody Hurts" scene, replaced by a white truck. After the commercial break, it changes into a white convertible. The number of lanes also changes during the commercial, from one each way to two each way.
Tractors do go on the smaller highways esp if they go past fields. Some farms have fields that are a mile or two apart on the road and farmers will take the two-lane highway to them. They don't always use on/off ramps but will drive directly into the field from the highway.
- angelinhel

The van appears to be on the road by itself for most of the trip except for the "Everybody Hurts" scene and the part where Daria has to use the "facilities" during a traffic jam.
Traffic jams up at odd times, usually for no apparent reason. the bottleneck effect from going to 2 lanes from 4 is also an issue. Driving in CA, there are pockets of stop and go traffic that mysteriously appear and break up with no stall or accident to account for it, before and after there are few cars near you. I would imagine this happens everywhere.
- angelinhel

When the fashion club goes to the diner, and they were standing talking about stretch pants and Stacy starts worrying if she is wearing stretch pants, then Sandy goes over and tells her that they are just leggings, there is a sign that says "Steaks in the back" that comes and goes away.

The Fashion Club members are all Freshman at this point, which means they should be around 15. Too young to get a license, in other words. Joey, Jeffy and Jamie are in the same grade, so either they "borrowed" one of their parent's cars or their a bit old for their grade.

Trent doesn't play a "G" chord in Road Worrier when he says he does.

Trent's goatee disappears when he's talking to Daria sometimes. (Ex. the scene where he's ending up the quote,"Like no money, no job, you live with your parents and you still can't play a open-D tuning.")

Most glue-guns aren't battery operated, and it does seem like a hot glue-gun, so it probably shouldn't be working in that last scene.

Double Meanings:

Daria and Jane are in Jane's room right after Jane's sculpture falls apart
Jane: "C'mon, I think Trent's band might have an opening for a new Fly Girl."
Daria: I think I might have an opening for a new friend...."

This could have a double meaning. Obviously Daria was saying this to Jane because she did not want to go down to the basement since she feels so shy around Trent. But it could also mean that Daria "might have an opening for a new friend"...that "new friend" being Trent. Hmmmm.....

Pretty much everywhere in the episode where Jane has her glue-gun

Aside from the obvious Freudian symbolism, Daria keeps telling Jane, "Don't come near me with that thing" or "Don't point that thing at me". Meanwhile, Jane is trying to hook ("glue") Daria up with Trent.

Daria and Trent are waiting by the van, while Jane and Jesse are off looking for help
Trent:  You know Daria, sometimes it's hard to believe you're in high-school.
Daria:  I find the situation unbelievable myself.

She might have also been referring to the entire present situation. She's finding herself attracted to Trent, she's trying to impress him (she wore lipstick and a different outfit), and everything's going wrong (or at least not smoothly). She bumped her head, sat in the peanut butter sandwich, had to go pee in the bushes, got stung on the arm, broke her glasses.  Maybe there's even a little irony: Here she's trying to make a good impression, worried (for once) about what other people (Trent) think, and nothing is working out. In the end, Trent tells Daria she's pretty cool anyway, because he's not too concerned (or maybe just oblivious) about that kind of stuff. Which is really the type of person Daria would be interested in anyway.

Daria, Jane, Trent, and Jesse are in "The Tank", playing the "Picnic Game"
Trent:  I'm going to the picnic and I'm bringing asbestos insulation, brine shrimp, the cryogenically frozen head of Walt Disney, and... a dromedary.
Daria:  I'm going to the picnic and I'm bringing asbestos insulation, brine shrimp, the cryogenically frozen head of Walt Disney, a dromedary, and... a Euro-centric view of world history.

When Trent says 'dromedary' he raises his eyebrows.  When Daria is repeating the answers, she does the same thing.  Now, it's Trent's first contribution to the list, so that's probably why he did it.  Daria, however, really has no reason to.  Except that Trent said it, and it starts with D... hint here?  Perhaps Jane set the order on purpose...
According to the Latin one of its pronunciations is "dromas," which in the Greek means "running." But a camel is slow and we know it can go for days without water.  Now here I theorize. Road Worrier planted the seeds to what I think might happen between Daria and Trent- it's off and running. But I don't see it happening anytime soon. It's going to be a very, very slow process, like I said. And a camel has humps. This situation is going to have its share of difficulties. Any relationship has humps to surmount.