If you are taking a lot of winter trips in that temp range put some heat tape on your hose. When I fulltimed I had one hose I wrapped with tin foil (distributes heat better) and tape heat tape to it with electrical tape. Heat tape available at most Home Depots. If just a few trips fill your water tank and use water from the tank.
Use a pressure regulator or sometime in the future you will wish you had. Repairs can be expensive
If you have more than one slide out you may consider buying an extra length of sewer hose. I have pulled into RV parks where I had to pull forward enough for slide to clear a tree and sewer hose was too short. Disconnecting and running around looking for an extra length of hose can be a pita.