should have been tipped off by the 14-32, its probably a 6 or 7 speed (most likely 7) with freewheel.

finding a used crank that will fit the bottom bracket might be easiest, if a 24 tooth cant be put on it. My 7 speed from 90 or 91 was able to take a 24 tooth granny.

ps gearing aside, if this bike is in fact over 20 yrs old (or 15 or whatever) all the bearings should be repacked before doing any sort of trip.