Welcome to the RV world and this forum. It seems like you are getting everything under control. Your experience working on jets will be of great value. There is an immense amount of information available on these forums and some true experts on just about every subject hanging around to offer help. And a search function to look around with on just about any subject.
I'll offer a couple of suggestions up front. Check for water leaks. Get up on that roof and inspect all the caulking. Poke at it a bit to be sure it's actually sealing. Check your window frames, etc.
Then some day when you have lots of time get underneath that chassis and spend lots of time looking around. Inspect everything very carefully. Look for rubbing fluid lines and any wiring showing problems. You will probably find lots of things that need to be corrected.
Regarding a separate black tank. That does not seem to be very common at all, but then you will have to pretty quickly learn to conserve, conserve, conserve, water. It's an art to be leaned when not camping with full hookups.
But for now go have some fun.