Heating/Insulation advice
 

I have a weekend cabin that is nothing but studs and siding including the cathedral ceiling - no insulation. The floor does have closed cell insulation. Unfortunately the wood is all gorgeous wormy chestnut which I hate to cover. Any suggestions on how to insulate? Insulated external siding? SIP for the roof? Or since it's a weekend home, should I just out-heat the place by increasing the number of gas heaters? I currently have one 40,000btu gas stove/heater that can keep it in the low 60 dgree range on cold winter days but I'd like to use the place in the winter more often. Maybe if I get two blue flame heaters to assist? Remember it's only used 1 or 2 nights each weekend. Should I assume the cost of the siding, roof, ect. would never be exceeded by the higher gas bills? Please advise I love the place and want to do what's right.

knowing where the cabin is located would certainly aid in getting useful suggestions. a few photos if available also helps.

Central Pennsylvania. Additionally, when not in use I keep cabin at 45 degrees. Gas bills are about $60 a month during winter months. Again I only use it on weekends but want to get it warmer.

It is safe to assume that removing and re-doing the siding as well as adding a sip roof would be a long term ROI calculation on the fuel savings along and especially at only $60 per month.

If you are trying to preserve the look, that does seem like the best alternative though.