"Dry" Camping - Cold Weather

For the first time we are "dry" camping - that is we did not load our camper with fresh water for this trip. We have been traveling from Montana to southern Utah and will return to Montana in about 2 weeks and will likely see night time temps down in the teens when we go through Jackson, Yellowstone and back into Montana.
The camper was previously winterized in Montana since we had subzero temps there before we left, all water lines are blown clear, hot water tank is empty.
So, what we've done is carry 4, 1 gallon water containers for potable water use, using them and filling as we go. We are using both the grey and black tanks for appropriate uses. When we get back to cold country I'll add a liberal amount of Pink Antifreeze in both tanks and keep the sink traps filled with it too.
Hopefully, when we get home the temps will be sufficiently high (above 20 degrees, or so) to allow me to dump the grey and black tanks. If not I suppose I'll add a bit of warm water to the tanks to get a dump.
I think I'll also leave the dump valves open ... at least the grey tank to make sure the dump valves don't freeze during the winter.

Any thoughts on how you folks "Dry" camp?