If you are talking about the 10' X 12' Harborfreight greenhouse, I just built one amd might have an opinion or two that might help.
1. The box weighs just 230 lbs and unit doesn't gain weight-so lifting finished unit by 4 or 6 strong men wouldn't be hard.
2. Skidding it on that sheet metal base would shurely damage it.
3. The base (foundation) is made to fit in a ditch so interior dirt secures it from blowing away. Its relatively easy to level that base as a small unit-might be very difficult with a finished greenhouse.
4. Why do you desire to build it and move it? Time would be saved by just rototilling now and building it in place.
5. I built mine on deep gravely fill and already determined I must wait until it settles a year then must relevel it. If I build another I will just ditch the perimiter for foundation and avoid loostening as much soil as I can.
6. I am a healthy age 70 and built mine with no help-but then I know more cusswords then most folks.

Thanks for the comments knotbored.
However the GH that dadlonglegs and I have only weighs 54 pounds shipping...a whole different thing. One reason for moving was to move it next to the house this winter to pipe heat into the house.
It appears the dadhaslonglegs has locked himself in his GH or has gone on vacation..so lets let this post die a natural death.