Hi Blaze n,
An engine retro fit is going to be a 10 on the 1 to 10 dificulty scale.
You will have to re-engineer pretty much everything in the engine compartment and some custom parts will have to be fabricated. This will cause issues while traveling as replacement parts are not going to be off the shelf available at an auto parts or RV store, or you will need a mismatch of random parts from different vehicles.
In my opinion you are much better off rebuilding your original engine/drive train. You could do things like add fuel injection to help with fuel mileage and power if that is one of your goals.
Shifty722 (aka Bill)