A friend years ago made a trailer from highway guardrail material (the stuff that's bent in a W shape. If you could find 4 lengths of that, it would support the truck as you roll it off the pond. Or temporarily fill the pond where the wheels will roll (assuming they still turn) with gravel (crushed rock would be best) to form a causeway. You'll need hip boots.
Then some 2x10's on the lawn in a "crossing the swamp" fashion (leapfrogging the 2x10's under the wheels) would protect the grass.
Looks like a nice project.
