My opinion would be largely based on what size your 7 speed freewheel is. It depends on how much stuff you will be touring with and how strong your legs are/ how big a gear you want to push. If I were to assume that your cranks have a pretty standard 74/ 110 bolt pattern, They will fit, and I would suggest something like 24, 36, 46 chain rings. (better to have low gears and not need them, than need them and not have them.) An old favorite saying.