Thanks for all of the excellent suggestions! I think every suggestion is better than my ghetto pallet/floor jack contraption. Let me try to summarize, in order of ascending price.
-Fold down back box, remove back legs, use hand truck $0 (thanks, mod)
-"Pin wheels" dolly set ~$36 on eBay (thanks, cadillacman) cheaper at Wally World (thanks, YellowDog)
-Manual lift cart made of wood $? (thanks, YellowDog)
-Manual lift cart made of metal $? (thanks, mod)
-Pinball skates ~$115 (thanks, xray2) those things win most clever, I think
-Modded Sears Hydraulic Lift $90 + wood (thanks, mrbill2084)
-Harbor Frieght Hydraulic Cart ~$260 (thanks, Oryk Zinyo)
I need to buy a few more pins to justify the higher-priced options here, and I don't move things around very much, so I think I'll get a dolly set. I really like the pinball skates, though. I had no idea such a thing existed.