Jumping in the deep end

So I'm working on a short film a student at UT is doing for his senior thesis. I'm used to shoots involving lighting rigs, multiple cameras, sometimes external sound. I've worked on a variety of projects, with enough equipment to fill up a car's backseat, trunk, and passenger's side. Today, we rented a Budget van to hold all the equipment for the weekend's three "small" shoots. On a future shoot, we'll be renting two.

Frankly, I'm not sure I'll be able to handle this. As Assistant Director, I was originally only going to be helping conduct the set on shoot days, until the other two AD's both dropped out. I stayed on anyway and told the director I would still do the film. Our first day of shooting is tomorrow, and if all goes well, it'll only be a couple of hours worth. But from my experience on sets, I know the chances of all going well. However, I only have three options at this late date: pull out entirely, ask for a reduced role, or suck it up and do my best. Since the first two would mean leaving the team in the lurch, they're not really options. I'll just take it as it comes, and do what I know how.