Strip the house out first. Disconnect electricity and gas (very important). Empty the house of anything not built in. Clean up after every task, or your work site will become overwhelming. Remove all the interior trim. Remove the doors and windows (most of these will be reusable). Remove the cabinets and bookshelves. Remove the plumbing. Remove the lighting. Remove any special architectural features such as fireplace mantles. Remove the wall and ceiling surfaces (whether drywall or plaster) and dispose of it. Remove the drywall nails from framing lumber while it is still in place. Remove the insulation.
Remove all non-load-bearing walls once the strip-out is complete, using the sledges and saws (those parallel to the ceiling joists). Do not remove load-bearing walls until the roof and/or upper floor is removed. Remove the roof next. Use a safety line on any roof steeper than 6-12 pitch. Shovel off the shingles, pry up the sheathing or plywood, then disassemble the rafters or trusses. Work from the top down, removing the attic floor, then the load-bearing walls that are clear from above. Saw out walls at the corners, then drop them whole, where they can be disassembled for framing lumber on the floor. Drop the exterior walls last, from the top down.
Begin the third step, materials processing, on the first day. Inventory and package materials for transportation. Log cabins present a special challenge if the logs are going to be reassembled. Inventory and mark each log for which wall it came from, and where on the wall (e.g., fifth from the bottom, Wall A-3).