schools are allowed to reimburse you for your gas in the same way there faculty is reimbursed for trips in there own cost. Which is usually round trip as long as you don't not make any other stops in between, your food and beverage can also be reimbursed you just have to provide a reciept.
I only had one official where I flew somewhere and that was paid for me and my parents. Otherwise their gas was reimbursed when driving. My meals and expenses were paid for while I was there and I think my parents went out to a nice dinner with us at each school I visited.