Ditto Ken. We have a 550 Ultra (cabinet doors) but no A/C or furnace.
Most of our clothes go in the upper cabinets - you can fit a TON of clothes in those cabinets, especially if you choose light-weight layers. It's all just folded up in piles (I'm no Marie Kondo) so cabinet doors keep the mess contained. Packing cubes (or more compact folding) would probably increase the functional storage space by quite a bit.
Our day-to-day clothes (plus long underwear, fleece jackets, sun shirts, etc) go in the upper cabinet. Smaller items like underclothes, socks, handkerchiefs go in the lower cabinet.
Outerwear (insulated jacket, rain coat/pants, hat & gloves, sun hat) goes in the front storage cabinet. Stuff sacks (or packing cubes) work great to keep things compact and contained. This might be the kind of thing to keep in a bag/bin on the upper bunk - don't need it all the time, but accessible if the weather turns.
We keep enough clothes in the camper for about two weeks - we're a bit dirt-baggy and re-wear our clothes as often as we can so our timeline depends a lot on the weather/humidity. We just plan to do laundry as our clothes/bedding requires. I keep a small bag of Tide pods & a few dryer sheets in the front storage compartment.