Start with the basics:
power adapters (dogbones, extension cord)
sewage hoses and adapters
chocks, leveling blocks (if needed)
Household goods will depend on your RVing style:
Corelle dishes vs. paper plates
A full set of pots & pans vs. a couple total
Sleeping bags vs. sheets, blankets and comforter
Full set of towels vs. minimal
Electric appliances vs. old fashioned camping style (coffee maker, toaster, etc.)
Dedicated TT bed pillows or bring your regular pillows
It will be very tempting to buy things because they "might be convenient", but it's better to wait until you know you really will use them. Do a weekend driveway campout using stuff out of your home and see how convenient they are for you. Then you can decide what to buy. You'll also be able to identify those things that are must haves.
I find that I like the ability to just throw a couple items in a bag and go, so I have dedicated tableware, cookware, linens, clothes, etc. Other folks will have very little stocked in the RV (often if they use a storage facility) and spend a few hours to a day stocking the RV before a trip.
