It's very much as described, and I would add that it's run by a very nice Mexican family - Pedro Cura and his sons - who speak fairly good English and are extremely welcoming and friendly. They have al pastor (pork) on the vertical spit and carne asada (beef) from a standard grill, all served in the standard Mexican style on doubled soft corn tacos topped with lots of onions and cilantro, a lime half, roasted potatoes and a little tub of creamy and VERY hot green chile salsa. DO NOT MISTAKE THIS FOR GUACAMOLE.

Tacos are $2 each, and a couple or three should fill you up.
Mr. Cura says he moves around from week to week, depending on where he arranges to set up his tent - he likes to stay on Preston, though, where he gets a lot of business from Mexican folks. He says most NorteAmericanos prefer Taco Bell, but I told him I thought we could find him a few exceptions around here.
Don't know just when he'll close today - it's pretty much a matter of how busy they are and when they run out of meat - but I'd guess they'll be there until 4 or so, anyway.
I have Señor Cura's E-mail address and will try to arrange to get information from him about where they're going to be each weekend, and will post it on the forum for a while.