I have a different take on the bike rack on the pin box. I have a Trailair pin box. It has a flat surface on top allowing me to mount a receiver on top.
Here is a link to a thread I started when installing the receiver and bike rack. Bike Rack on Pin Box.... However I have changed the bike rack to one that the bikes sit in rather than hang from.
I like it much better. They don't bounce or move around. Unlike Dave, I don't have any problem with the bikes on the front of my trailer. I don't feel any wind effects on how the trailer handles. Don't know they are there. I did try to put a cover on the bikes but it didn't work well, so I have bikes that are aluminum and they are out in the weather all the time.
As to taking the bikes off the rack I use one of the folding plastic steps but I do have an advantage being almost 6'3". So yes if you have short legs a ladder might be necessary or use the tailgate on the truck.
One advantage to the bikes being on the pin box is that they don't bounce around on the rear of the trailer. Heard a few problems with the bike rack breaking, the hitch breaking and loosing the bikes or dragging them down the highway. That won't happen with the rack on the pin box.
One problem with one being on the pin box.. You may not have enough room to mount the receiver and/or bike rack. Short bed, or pin box does not extend much beyond the front of the trailer.
Hope this helps...
FWIW
BC