Your truck looks lower than mine so it maybe its not as bad. The problems I had was if the ramps weren't locked down tight enough the tracks would easily dislodge them, uneven ground made it worse and if it was wet or muddy it made the smooth steel upraised dump body's floor impossible to traverse. Its low trailers for me!
The truck is probably not lower. In the pic, I have raised the dump box. This allows a smoother transition moving the mini out of the box and onto the ramps with out the machine pivoting forwards on the tracks once it gets past it's center of gravity. This doesn't happen when the ramps are close to the same angle as the box (or as close).
To stop the ramps from sliding out, we ratchet strap them back to the trailer hitch (chain hooks) on the truck.
Yes, wet or muddy weather can make for a slippery ride. Forget even trying on uneven ground. I'll usually look for a hill or a slope and point the truck downhill to reduce the angle of the ramps.
I prefer loading onto the trailer, however, in situation where I only need the one vehicle and have to bring the chipper,, this gives me the option to also bring the mini.
It also only works if your leaving the chips and logs on site. Other wise I'll bring the second truck and trailer.