As far as what we put where, we're still in the adjustment phase, but initially we put the stuff we use outside or infrequently in the seat bins. This also happens to be strictly camping items, and stays permanently in the trailer. By the way we found some Snap Ware containers at Lowe's which measure 11 1/2' W x 15 1/2' L x5 3/4' H. Tilted they go perfectly into the bins and can be stacked double. They really help to organize and save space.
Stuff we access regularly goes in the top cabinets.
We also pack a 12x12 canopy between the seats along with a poly ground mat. We put the bed supports and the cushions down so that we can sleep without moving things around too much for overnights in route. The porta potty goes under the bed while traveling so we have access if needed. This is also where we put the potty when we sleep. Just slide to the foot of the bed, slide out the potty and have at it.
We use a Dometic 970 series toilet. Can't remember the exact model, but it has the 2.6 gallon holding tank, pressure flushing and tank gauge. It fits neatly between the seats while traveling. During the day while camping, when we have access to public facilities, it fits nicely in the seat bin for the potty.
Everything else we put in the TV, with the exception of camp fuel, stove and lantern, which go in a small cartop carrier on the Tribute.
By the way, the previous owners installed a small lockable door in front of the right wheel for storing extension cord, hose, chocks and such.....highly recommended.
Any more questions, just ask.