If you plan ahead, one of the best boots you can have is a tyvek envelope. Go get one from the post office (Priority Mail envelope). Tyvek is the stuff that you can't rip. I cut it into 6x6 inch patches, you can store several in basically zero space and it's even stronger than bills or candy wrappers (two of the favorite boot materials).
This all depends on the gravel too. I ride 8 miles a day on gravel, and "gravel" can run from packed clay-bound stuff that's practically as smooth as pavement to jagged course crushed stone that will cut the hell out of tires. I doubt it's the latter. You probably won't have any problem at all but of course always be prepared.
__________________
Work: the 8 hours that separates bike rides.