The planning and thinking part especially!
Let me add this. Check the floor for rot, check the frame for integrity. You don't want to remodel the interior and THEN have to take it all out to do a frame off floor replacement.
Use the SEARCH feature here - go to advanced search and look for Full Monte threads. There are some really excellent restorers here (not me, I could do it but I don't want to!) who have done excellent work.
Be prepared for some very big ticket items (axles, flooring, frame repair) and do realize that you'll almost certainly be safer replacing all of the propane appliances.
Once you have a solid frame, good axles, tires and brakes and no leaks, you have a rolling tent. You don't have to wait until all systems are complete to use it.
And most of all, welcome to the forums. You've come to the right place to find the help and encouragement you'll need.