Hopefully this will help. We have a Thor Challenger 37TB with 1.5 baths and a washer/dryer.
In the past 11 months we have traveled 17,500 miles through 30 states, dry camped for about 3 months in Key West and LOVE the coach. (Note: we are not full timers - about 7-8 months per year.)
There are 2 dump valves. One about mid-way, the other all the way back. We store our stinky slinkys in the far back compartment by the back valve.
I mentioned the washer/dryer earlier simply because without 2 40 gal tanks, dry camping and doing wash would be mutually exclusive.
When we dry camped we used our on board generator combined with 4 6volt batteries. We showered each day, did 2 loads of wash in 5 days and generally lived a normal coach based life. Without the 100 gals of fresh water and 2 40 gals of grey water - you simply could not live this way. The DW will not make concession for comfort. So every 5 days we dumped and refilled fresh water. Most others used blue pods and a fresh water bladders. I am not into either of these.
So yep, 2 hook ups but no big deal. after so many days of dry camping I have it down to a science. Also, when we are in a camp ground for more than a couple of days, I carry a Y adapter and run both sewer lines into 1.
I cannot say enough good about the Challenger for dry camping. After owning it, the standards for dry camping are very high.
Hope this helps.