I spent $22k to replace my 4x4 pickup with a 2017 RAM Promaster 1500 cargo van, so I could stand up in it.
I spent $750 on the build out, not including camping gear I already had from my setup in the pickup.
I built an insulated bulkhead with locking door for stealth, privacy, and a place to mount things. I mounted my solar controller on the bulkhead on the cab side, as well as coat hooks above the passenger seat for drying things. The cabin side of the bulkhead has hooks for my "closet" on one side, and secures the back of my "kitchen" cabinet on the side near the cargo door.
I built a freestanding bed in the back (not supported by the walls) with storage underneath. At the rear is a small garage 5x2x2 where the generator, water buckets, tools, shovel, sand ladders, firewood, folding table, etc are stored. Also has access to one of the saddle bags (saddle bags are storage areas over the wheel wells). I store 6 gallon water jugs and drinks in this saddle bag.
I did not include powered refrigeration, plumbing, or electrical beyond a solar panel on the dash to run the Maxxfan and a couple luci lights, a shore power strip for when I have shore power.
The rig works great for camp hosting and general camping and trips. I am usually out for 6 months with weekly trips to town. I was hoping to use an outside shower when travelling, but that never works out so I do a Basin bath inside. I did use my shower tent as a safety shower during my camp hosting job (nasty forest service chemicals).
I invested in Ryobi battery tools, which I charge up at places like the library or the laundromat. Battery drill and battery air compressor are indispensable. I even had a Ryobi weed whacker for use in maintaining the campground (short lived for a weed whacker I do not reccomend). I have an inverter which I never use. I got a bigger inverter and I don't use that one either.
I own a Ryobi generator which I used frequently in the pickup, but rarely in the van.
I invested $17k in a home base to have a shaded carport for the van (its AZ, you do need shade from time to time). I spend 5k for rent and utilities on the home base, which includes security, a pool, and mail forwarding service etc.
My startup cost was $22,750 for the van. My startup cost for the home base was $20k including about $3k in repairs. Annual budget for everything is $8k.
-crofter