For mods, I like
http://www.modmyrv.com/
For stuff you need, it depends on what you do. For home stuff, you need kitchenware and plates/silverware. I use disposable goods so I don’t have to wash. You’ll also need linens (sheets/towels).
Did you get some sort of starter package from the dealer? This would have your sewer hose (get disposable gloves!), fresh water hose, and preferably a flushout hose (grey colored) and clear sewer elbow with hose hookup for flushing.
You’ll also need wood for leveling under the wheels. I happened to have a bunch of dogear fence boards I cut into 16” lengths. Good for leveling and for putting under stabilizer jacks.
For cleaning, I have a dust buster, whisk broom, and a tub of household cleaning goods.
I think that’s the basics.
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-Scott, DW, DG, DB, and DD
2011 Passport 2590BH
2009 Ford F150 SuperCrew F
X4 5.4L w/Max Tow