We did these last summer. I meant to post them sooner but ....
We ordered the trailer with the table base uninstalled. Making it's own base lets us move it for ease of seating and gives a flat floor at night providing floor space for the dog. The compromise is that the table is not as stable as if the base was screwed down. The back table top was cut down to use in the front giving an extra few inches(about 6) over the stock table.
A piece of plywood with an wood edge for stiffening makes the permanent bed. Cleats underneath hold it in place. The side storage bins are easy to get to by rolling back the mattress and because the plywood sits on top of the seats, the portapotti fits underneath. Raz