I use 6x6 eucalyptus cribbing blocks on my tracked equipment, but of course I just get to crawl on top of them like steps
Cribbing is the cheat code. Yes, it's 'only wood' in 2x4 or 4x4 sections, but if you ever do armored vehicle recovery, or work first responder for vehicular accidents, guess what they use.... The very same. The compression strength of SYP and similar vegetable matter is seriously impressive.
If you're going to stash some cribbing pieces, recommend you go for pressure-treated or at least apply lots of used motor oil or boiled linseed oil to prevent rot, as it is sure to get wet in use.