When I picked up my 70A from the individual I bought it from, I purposely bled the boom down to the ground to make it easier to load, position and tie down on my trailer. Once I got it home, unloaded and sitting on the ground, I obviously couldn't drive underneath it with the mast down on the ground. I just faced the tractor the opposite direction and pulled up along side the loader so I could plug the hoses in. Then I raised the masts into the normal "parked" position. Unhooked the hoses, pulled the tractor around, drove underneath it and mounted it up.
Anytime you leave the loader parked for extended periods of time, there is the chance that the masts my bleed down to the point that you can't get back under it. I always try to park it in a location that I can get along side of it on the hose side in case I need to raise it a little so I can get underneath it. If you can't park it such that you can get along side of on the hose side, you can still raise it back up by spending a little money on a set of extension hoses.