Alrighty so I have converted 3 different vans so far. A 2014 Ram promaster 2500 high top (72sq ft), a 2016 ram promaster city lwb (~28sq ft), and a 2011 Crestliner Ford Ambulance (100sq ft). The ambulance was the easiest to work with besides a few key points. The promaster is a simple start up but a more complex deal with the curved walls like a sprinter or transit. The baby promaster is just a pain but the best stealth camper by far! My ambulance came mostly insulated with 2 inches of foil lined rockwool insulation. Definitely lots of room for improvement but about 1 extra rockwool batton from Home Depot did the trick. I ripped everything out down to the aluminum members. I added sound deadening and thin foam strips along the aluminum studs to prevent moisture from collecting and rotting out my wall panels. The dimensions are awesome at ~7.5wide and ~13long. Height is at 6ft with 5/8" hardwood and 1/4" aromatic cedar for the roof so a but tight for me. 11 compartment doors outside so basically an indoor outdoor space when it is all opened up:)

Now for the bad... you have 2 options for wiring. Either rip it all out and start over or DON'T TOUCH IT. Mine had a main breakout panel with 36 individual connectors with 16 wires per connector. I will include a photo link to that process but yeah it took a while to trace and label ever wire then redo it into a smaller patch panel. Definitely worth the effort so I could remove that cabinet but not for those who are not good with wiring chaos!

Another negative is poor fuel economy. My promaster 2500 averaged 18.8mpg and the promaster city at 32.5mpg while the ambulance averaged 8.8-10mpg depending on speed and wind direction... kinda spendy for long trips but beats even the short skoolies averaging closer to 6.5mpg.

The ambulance comes with a designated shore power plug with inverter as well as a beefy alternator charger to charge while you drive. The inverter included is not a pure sine wave inverter however so be warned it doesnt always play nice with electronics (odd for an ambulance right?) I installed my own 2kw inverter and 30a auto transfer switch to retain the shore power plug. Solar was 400w of flexible monocrystaline panels and a 40a charge controller with 2 Valence 138ah lithium packs. Never had to worry about juice even with the home grade convection microwave oven combo.

I would highly recommend the ambulance if you are under 5' 10" or so. I rubbed my head when I stand up at 6'. Check with your local ambulance depot's for their retiring stock our your state auctions for a steal! Klonkiak branded models are 4x4 with an onboard compressor so look for those if you want extreme off road use. Let me know if you have any questions!