I made 2x10 ramps. 45 degree cuts and staggered back, 3 levels, first level was extended out a bit so tire would hold the ramp down befor accending the next 2 levels. Stapled sandpaper to the bottoms.
I've had that poster in my shop for awhile now. Its my go to 'What are you doing today?" answer.
Just bought a 1984 boat, motor and trailer to teach the grandsons about fishing and boating. It needs a lot of PO un-puttering.