I havn't moved mine in a few years, but was doing it on a weekly basis for awhile there. I was afraid of those short, steep ramps, so I bought the attachments to build my own ramps from Home Depot. I think they were under $40 for a set of aluminum ends that attach to 2x12's.
I bought ten footers and was fairly satisfied with that length. They were very heavy to lug around, but would slide up under the lawn mower with the tail gate down while driving. The wood was a little slick, so I addes some traction tape that lasted about a year.
I started out driving up into the bed, but backing down really scared me. The angle wasn't bad, but my imagination was on overdrive on what could happen!!!!
I found that backing it in was pretty easy, and getting it out was MUCH better.
Now that I have a trailer, that's the only way I move my mower around. I used to 2x12's for something else and gave away the ramp ends.
Eddie