Read all you can here and look at the conversion pics/videos. How long are you planning to keep it? Is it worth a lot of time and money? Would you like to remove the kennels and use it for traveling/camping?
If it would be worth it to you strip it down to bare metal, remove the inside panels and crappy insulation. Then you have a clean slate. Insulate it good and build it the way you want it. You could run off of a generator, wire it for shore power or solar. Just research here and you will have all the info you will need. Its good to have you here and good luck. Oh, and don't hesitate to ask questions.