Insulation, Radiant and Vapor Barriers - Insulation in three season cabin?

We have stripped the interior of our 1920's three season cabin in Pa. down to the 2" x 4" studs and have had it rewired. The exterior is painted cedar clapboard with no vapor barrier. We do not want to strip off the exterior siding to wrap it in tyvek because the siding is in good shape. The roof is metal over apshalt shingles and has a ridge vent. The ceiling will be a modified cathedral. We would like to use a combination of t&g wood and drywall for the interior walls and ceiling. I am unsure of how and/or whether to insulate. Loss of heat is not a concern, however creating/avoiding a condensation/moisture/mold/mildew problem is a big concern of mine. The cabin sits through extremes of temperature and gets virtually no winter use with the exception of one or two visits to check on it's safety/security. We have a fireplace and a propane heater to warm it up when we use it in cooler periods in fall and spring. Water is shut off in October. When we stripped off the old interior homosote and cheesy paneling there did not appear to be any significant mold problem - just a pretty musty old smell in the homostote. There was no insulation whatsoever in the cavities.

My Questions -

I was thinking of using blue foam board insulation cut to fit snugly into the joist cavities and sit tight against the exterior between the wall joists. That would still leave a cavity between the foam board and the finished wall surface. Would that create more problems than it solves?

Should I use a moisture resistant drywall, like the kind you use in bathrooms?


What would you do if this was your cabin? We need finished walls over the studs because the wiring shows and frankly the joist cavities are not very pretty to look at.

I appreciate any suggestions. I have heard that spray-in insulation would be perfect but I am worried about the high cost and the inability to make any changes within the wall cavities after insulation.

Sorry this is soooo long,
Susan