I have a 1975 Dodge American Clipper class C so I can offer some "been there done that" advice:
1. Replace all the rubber. That means tires, belt, hoses, etc. Including fuel lines. Vehicles that old can have pinprick holes in the fuel line which not only drop your mpg, but can be very dangerous.
2. Have the propane system checked out thoroughly. Again, a leak could be very dangerous.
Now you get to the rest of the stuff:
3. Reseal all the edges, windows, vents, etc. At this point, just seal so you don't get anymore damage than may already be there. Then you can do repair/reconstruction work on old leak damage. Remember to always check for leaks after a rain - it only takesone storm to do a whole lot of damage.
According to vinwiz.com, your chassis is actually a 1979. This is common to have the chassis be a year prior to the house. It is also a 440 engine. The 440s commonly have overheating issues due to the confined space in the doghouse. So you may find you need to make some adjustments for best operation.
Take it slow and easy and you may find you have a great RV. There are many on the road today.
Please feel free to PM me if you'd like more resources, etc.
