Best of luck on your conversion! How radical do you plan to get? Are you planning to full-time it? It sounded like you were...just clarifying. There are all kinds of great ideas around the this site.
Most on here would tell you that insulation is key. I agree for the most part. Since our bus will be used for travel, not so much staying put, I think that the super bus heaters and open winders will do just fine.
If you intend to stay put for awhile, insulation would be good. There's really not much insulation there.
Do you plan for a bathroom? Kitchen? etc? Look for a donor camper if possible and steal as many usable parts as possible...that's just my 1/50th of a dollar. I think you have a great platform to work with. Oh yeah, pics are a MUST! If not, Smitty comes knockin'!