Okay, if you are planning on extended sub-freezing camping, the R-Pod is not the best choice. You would need a unit made for four-season use. Those have enclosed tanks that have heat ducted to them so they won't freeze. The exposed tanks of the R-Pod can freeze. That being said, if you only anticipate overnight freezes that are in the mid-20's and higher and the temps will be above freezing during the day, then you can have water in the tank and use it. If, however, temps are projected to be consistently below freezing, it is best to drain the fresh water system and winterize it. Some people use compressed air only. Some use RV antifreeze only. Some use a combination of the two to make sure that the fresh water system won't freeze up and break water lines and/or valves.

When we made a winter trip, we winterized the fresh water system. We carried extra RV antifreeze and used that for flushing solids and after flushing liquids, added a little RV antifreeze to keep the valve wet. We carried an 8 gallon Hydroller water carrier in our tow vehicle since it was heated and moved it to the R-Pod when we stopped. Our drinking  and cooking water came from that. Since it was always in a heated space, we did not need to worry about it freezing.

Showers were out so adult pre-moistened washcloths (look in the drugstore's medical supplies) like what are used in hospitals took the place of showers. A product for waterless hair cleaning also helps. If you are staying at a campground that is open year-round, it should have a heated shower facility. We were traveling and staying in Walmart parking lots or truck stops or other convenient places that lacked hookups and such amenities.

Winter camping with an R-Pod is certainly doable. It will be challenging though. As long as you are prepared, you can do so successfully.

RPods aren't made for 4-season camping.  They're okay to around 20 degrees if it warms up in the daytime.  If you want to spend enough money there are things can try, but usually people who cold camp winterize the plumbing and use bottled water for drinking and cooking and flush with RV antifreeze.

RPods are tight so they're pretty easy to keep warm inside.  They're small so they cool off quickly too though.

TT