Anyone can make a level 1 character on The Venture Co server, and get to Dalaran unaided; here's how:
1) Go to Stormwind or Orgrimmar
3) As a ghost, go to Borean Tundra by boat or zeppelin
4) Still as a ghost, run to Sholazar Basin and run up the avalanche
5) When you get to Icecrown, you will get a flying spectral mount
6) Fly up high towards Dalaran above Crystalsong Forest
7) As you enter the Crystalsong Forest zone, you will lose your mount, but if you are up high enough, you will land in Dalaran
8) Resurrect in the graveyard near the Violet Citadel
9) If you "miss" and end up on the ground, run back to the dam at the Decrepit Flow area and you should get another spectral flying mount.
However, you can also ask Pipkin (Alliance mage) for a portal, if he's on. He should be around just before the party starts. Reinisch can also try and buy a portal for last-minute arrivals, but that's a bit chancier.