Hello! My husband and I are the owners of the '85 Neoplan that you are discussing. Thanks for the compliments and the comments.
Geof is right, we've been very surprised...pleasantly surprised! It turns out that our two small propane tanks will last us 3-4 months and we've had no problem getting them refilled.
We use the propane only for cooking, not for refrigeration or heating. Our fridge is a 24V compressor style, which can run over a week on our batteries, and we use either electricity or diesel for heat. (We use the electric heaters if we are plugged in or if the generator is running). We also have an electric burner for cooking if we run out of propane or if we're plugged in. That has worked quite well.
If you're interested in reading more about the cooking/heating stuff,
go here, and scroll about half way down the page.
We've been living full time in our rig for 15 months now, including a 6 week stint of dry camping. There have been a few minor tweaks of the setup, but all in all, we've been very, very pleased with how everything is working. We typically go 10 to 14 days before we need to dump/fill, and between the generator, alternator and good batteries, we rarely need to hookup. The sense of independence is just great!
-Louise