The safari is about an hour at most, maybe, maybe 1.5 hours if you drive very slowly and it's very crowded, but I think that would be a big stretch. You stay in your car, not allowed out, and you just keep driving through (no stopping really) so it doesn't take very long. We've gone to Great Adventure, gotten lunch, taken it into the car, driven through the safari, then back to Great Adventure all within about 45 minutes. With the lines though, you could easily make 1.5 days out of Great Adventure. Are you going to go to the water park too? If so that would be about a day's worth of stuff. Honestly though, I can't think of any hotels right in that area, but my suggestion would be to look around the New Brunswick area which is around a 20-30 minute drive and full of hotels.
My husband wanted me to add that the monkeys in the safari can rip stuff off of your car. So if you want to avoid that, do the monkey bypass route.