I think you're going to run out of room real quick in a 21' trailer. What if you want to leave the bikes in the trailer when you stop because of bad weather? Do you want to unload the bikes every time you stop to set up beds? I would add at least another 5' to the trailer. You want a full size ramp door at the back, not some small one in the back or on the side. I would start going to rv shows or stopping at the larger dealers to see what suits you. Also, if you want to dry camp, a smaller trailer has smaller fresh water tanks as well. Showers will use up a small tank quick.
