Are you sure that you don't build vans professionally? All of your work is so clean. The upgrades are looking great man!
A heater is such a clutch piece of kit. We took a shakedown test to the Sierra Nevadas in Oct and our sink wasn't working but the heater was.
One night in Klamath Falls on the way home it was 17 degrees with a -10 wind chill. We had already been driving 6 hours and didn't want to continue home. The heater wasn't working at first (had to reboot it) but if it wasn't going to work, we couldn't stay.