If you have someone who is 21, but you're not 21, can you still get in just for the food?

Look -- get an over 21 friend to pick up a bottle of Popov, oj, & peach schnapps and have a party somewhere

No you can't get inside. The food trucks are usually outside so food is available. There is no kitchen inside.

There's no seating outside and its a bar so you can get food at the food truck but you can't go inside.

The only food here is courtesy of a food truck, so you dont actually have to enter the place for food. That being said, i don't recall much (if any) seating outside the establishment.

Unknown, but given the laws of Utah I would doubt it.