The happijac bunks are suitable if used as intended. They do move up on the opposite end when you put your full weight on the end but only and inch or so and it is the way the brackets that hold the bed attach to the track that moves the beds up and down. The beds could be beefed up easily by just replacing the plywood bed. As is I wouldn't want kids jumping up down on them. However, I've been up there, and My 200 lbs.+ son has uses them whenever we go camping, They are adequate but if you felt the need you can replace the 1/2 inch ply with 3/4 inch ply and they would be a lot better.
I did however put screw through the steps of the ladder before you even going out the first time. The ladder must of been meant as a decorator piece because it sure is not suitable for use.
The door is plenty large enough to put the bikes in fully assembled with no modifications. I have a home built PVC pipe bike rack I use regularly and put 4 adult bikes in standing up.
