Just camp in your driveway for a couple nights and you will soon figure out what you need as far as kitchen and bath. For the other stuff, get extra length of sewer hose and extra length of city water hose and possible extension for the power cable. Things like surge protector, leveling blocks (Anderson levelers work great), coax for any possible cable hookups (at least 25'), mattress pad, tool kit with screwdrivers, pliers, volt/ohm meter, etc. and after a few campouts you will gradually accumulate most of the stuff. Pick up some storage containers to put it all in so it doesn't slide around when you travel.
2014 Palomino Puma 25RS
2011 F-150 Super Crew XLT
Days camped in 2014 - 23
Camped 2015 - 47
Camped 2016 - 51 done - 6 more planned so far