OK, I'm thinking a combination of great ideas:
Best: Out of sight, out of mind. Since I'm on a variably sloped lot, maybe I'll dig into the steepest embankment, and make a U-shaped retaining wall, maybe 8 deep, 5 wide,3 tall, complete with roof for winter storage, and heck, while I'm at it, add a front door with a lock.... hmmm, maybe that'll do it!
In the meantime, I'll remove the towing coupler, and scribe my drivers license number or something in a remote spot, tack weld mounting bolts/nuts for engine, and use my unknown grade chain and generic lock to an 8 inch Bay tree to discourage the petty theives, then go in for a beer and relax.
Thanks for the input guys, much appreciated!