Hot water with a shower:
We got our hot water tank on sale but expect one new to range 350 to 650 depending on features. Ours hot water tank has electronic spark to start it which means you do not have to go outside to
light a pilot
light and is only
propane. Some water heaters are on demand electric and cost less or manual pilot
light propane while others are dual electric and propane. They do not sell hot water tank with all the hookups or outside cover, they are extra. Add taps shower head and pipes, drain install gas hookup to the list of costs though. For us as we go to wilderness parks hot water for a shower is a great idea and worth the cost. (adds to value)
A Thermostat controlled forced air Furnace can go 1000. you may be able to find a used one "Wayne Hill might have one". We have winter camped and a furnace is great at sub zero. Would not have purchased a trailer with out one.
In short do not know
Scamp resale values with and with out as we have a
boler. Still would not have purchased ours if no furnace. Hot water we could live without but then again doing retro fit now. In the end we all go by or own needs.
How cold are the nights in Oregon
Have shower pop-up drain installed, purchased hot water tank, outside cover, bypass kit, copper gas line, shower tap and spray unit; still needs some water pipes.
Just waiting for a break in the weather to do part 2 cut the hole in the side under the sink in the location of the original factory install.