Can't say strenuously enough--BUY A TRAILER.
NO matter how careful you are, or how many times you do it--all it takes is 1 time. Happened to melast summer. One ramp slipped and the other went, I flew off, my 700# Honda rider came down in slooooow motion right to me. 5 minutes later, I woke up thankful to be doing so. Note: Have done this 100+ times. .....best of conditions.
Main problem is ramp angle is too steep--haven't seen a viable design I would consider. Also, at the elevation of a pickup bed, a falling tractor can do a lot of damage. The BX is no light weight--even without the loader (1300# with the mower deck, I'd guess).
You can probably find a viable used small trailer for the BX for $400'ish. New ones here in Michigan can be had starting at $600, with steel mesh gate/ramp. Nothing great, just angle iron and plywood, car tires (2) and 2000# capacity. But will last as long as the tractor with reasonable care. Plus, you can use it as a big wagon around your property behind the BX.
Good luck!