Really, and I do mean really, big job. Peeling back the roof isn't too hard and there have been several owners that have done the job but sidewall insulation will be the cost killer. You can add the space age insulation but the windows will cancel out any benefit gained unless replaced with double pane glass. Plus many times the interior walls a glued or bonded in some manner to the framing. Difficult to determine if they could be removed without damage.
Do what ever is necessary to make the coach reliable and livable but don't go much further. You'll still have reoccurring maintenance even if the coach is showroom new so keep such in mind. Once you find the land you want for a final destination park the coach and install the needed solar equipment there but not on the coach. Then live in the coach while building something more permanent.
The elephant in the corner is putting everything into the coach with long range plans wrapped around it. One accident, catastrophic drive train failure, fire or such and the plan falls apart. Have plan B that doesn't include a state lottery.
