Welcome aboard! What you need? Love spending other peoples money!
I think the basic necessities to be a quality power inverter like a Hughes, quality sewer hoses, for your leveling legs we have the magnetic buckets that are invaluable, a dedicated and proper drinking water hose line, inline water filter with adjustable pressure gauge, sewer hose for hooking in to the clean out connection when you unhook and do your break down to flush the black tank if you have that on your RV, TPMS if not equipped, a backup camera is nice but not a total necessity, a black tank treatment you use each time you set up like Unique Digest I believe it is called that is the best, and a king pin tri-pod to have if your campsite once setup still has to much rocking in it. These are a great start along with some tools to fix minor issues.
Enjoy!