You might look into a tilt bed trailer. No ramps, the whole bed tilts down to the ground and just drive on. I just bought a 20' tilt bed for hauling my tractor and various other items such as cars, trucks, etc. Mine is 83" wide between the fenders but if you don't need one that wide they make smaller ones. Mine was $3140. but if you only need a 16' or 18' x 77" wide they sell for much less. Approx $2000-2500. Mine is an 8.5 x 20' MX Speedloader manual tandem tilt made by H&H trailer. They have a web site to look at. I picked mine up at a PA dealer. Hope this helps. There are many trailer Mfgs. on the net. Perhaps you could get by with a landscape trailer that has a full width gate that drops down also. Just some options to think about. P.S. there are some pics of mine in the photo section / other brands / mahanidra
George