mk216v,
Yes, we're in Bend OR. Happy to meet up and talk rigs sometime if you're in the area.
And because we're in Bend where our typical daily temp swing can be 40 degrees from high to low, we can experience below freezing overnight lows from September to May (or even early June some years) so four season prep is really a minimum requirement even for spring and fall use. The truck was originally built to live in SoCal and make trips south with motos, bikes and boards and even though well insulated, the propane heater that was installed was for brief use since it required a window or door open to function / prevent co build up. This worked for running it for a few minutes in the AM to take the chill out of the air, but wasn't an option for cold weather camping. We're in the process of installing an Espar D2 unit and just dropped and plumbed an auxiliary fuel tap into the fuel tank, and will start the heater install later this week. I ran this heater set up in my old Sprinter van and never had any issues. And it keep the van ridiculously warm for how little diesel it used. The second issue we're addressing is moving all of the water plumbing into the inside of the cabin - it currently runs outside / under the floor where freezing is an issue. By moving it inside and combining it with the auxiliary heater set to 45 degrees we can keep the water system active in the shoulder seasons between trips. The freshwater tanks will still be on the underside of the truck so I'm working on integrating a smaller interior water tank to allow use of the sink and maybe a quick shower or two during winter use. We'd add bypass valves so that the main tanks and exterior shower system could remain empty over the winter. I may even go with a removable 5 gallon tank to make it super easy.
I've also started work on redoing the electrical system to eliminate the external generator and add a lot more capacity to allow longer off-grid use, but that's a longer story that I'll cover in the future build thread.