Op...
Plain and simple: there IS no time to use the gps. There isn't ample time to look at a map, but The map will be a much better tool in the long run anyways. When in an unfamiliar area you will fall on your face. We all did.
If you get the seasonal job they'll teach you a route and by the end of the week you'll know that area better than your home town.
You've solicited responses from a lot of experience here. Instead of defending your stance, trust the process. My first experience driving was in a center 45 minutes away from where I was familiar and another 30 minutes further to get on area. I didn't know where anything was. You don't need a gps. Waste of time when on road, period.