Just do it. Use whatever gearing you have. Worst case, you have to walk some hills. It'll give you some time to reflect on the ins and outs of overnight camping.

I did some overnighters on my Gunnar cross bike a few years back. I only had a 130 BCD crank on there, and I was too lazy to swap the whole crank out, so I was limited to the 39t small chainring. I bodged together a few cassettes in the back to make a custom 12-34 nine speed, which worked OK with my short cage rear derailer. Friction shifting is nice that way. Still, my low gear was only 39x34, but that was OK for flat Central Ohio.