If the outer sheeting was done with a nail or staple gun, you can figure on losing most, if not all of the sheeting. Same for roofing - just figure on scraping the shingles and knocking the sheeting off. Make sure the trusses are tied together under the roof (usually a 2x or 1x something nailed to the underside of the truss along the peak of the roof) before you start knocking the sheeting off.
The rest - get a good sawzall (reciprocating demolition saw) and a bunch of good blades and cut the nails.
One thought - you might be able to remove the walls in sections. The roof I think will have to have the shingles stripped and the sheeting removed as described previously (BAH from below works wonders).
For the walls, take the sawzall and starting from the top, cut through the cap plates and right next to a stud all the way down to the sill plate, and through that too. Make the sections as large as you can handle/transport. Number or identify everything so it goes back together just as it came apart.
When it comes time to re-assemble, add a new 2x6 to the right of the stud where you cut the siding. Just to be good and strong, I'd use construction adhesive + nails or screws to attach it. This will give you a good nailing point to reattach the sheeting.
I'd consider removing the cap plates and installing new ones to properly stitch the walls together. (Of course, you could remove these before you cut the walls into sections.) Alternately, you could add another cap plate on top of the ones already there, but you'll have a 1-1/2" gap in the sheeting at the top of the wall. That may or may not matter for siding, but you'll need to tie the trusses down to the sheeting somehow to provide proper wind-lift stability. "Hurricane clips" (what we call them down here) usually only reach from the truss to the bottom of the 2nd 2-by under the truss. The sheeting ties the 2 2-by together at the top of the wall.
The cost to move a wood structure like this (assuming it could stand the strain of lifting it) is prohibitive.
Just remember that chip board doesn't like coming back off a wall in one piece. Unless it's screwed in place, unless you can gently pry it free and slip the sawzall in from behind to slice the fasteners, you'll likely destroy the sheet before it comes loose.
Great opportunity. Cost will be minimal if you've got a bunch of willing friends. The biggest PITA will be removing the roof and getting the trusses down.
I would think with the proper ladders, scaffolding, etc, that this structure could be a pile of trusses and wall sections in a weekend's work.