Without factoring in freezing temperatures, since spring is here. Is the RV going to get any use between camping trips or other travels? Like maybe the occasional overnight while it's parked by the house. If it's getting use between trips and the toilet is being used, leave a little water and a black tank chemical of some sort in the black tank. Toilet tissue and solid waste will harden in a dry tank and make if very difficult to flush later on. The water and chemical will help break down the solids and prevent them from hardening in your tank. We overnight in our MH next to the house from time to time, even in the winter of Northern Nevada. We use the toilet, but for #1 only. If we gotta do #2, we go inside the house. The tank has some chemical to help with deodorizing and a gallon or two of RV antifreeze so the urine doesn't freeze. RV antifreeze is relatively cheap for the protection if offers.
Kind of the same deal for the gray water tank. If you're rinsing stuff down the kitchen, or bathroom sink or shower drain that could harden or solidify you'll want some liquid in there to prevent that. If the RV is sitting un used while it's not being taken out, you don't need to leave anything in the tanks at all.
I'm sure others will chime in with good ideas as well. Like how to handle it when you did your black tank dump just before you're ready to pack out of your campsite and a family member goes and does #2 after the black tank is empty.
Gray tank is a lot more forgiving and you'd have to do something pretty crazy to mess that up. Black tank though is serious business in how it's cared for. Mess that one up and it will be very expensive getting it removed and taken care of. Not just for the cost of the RV repair shops labor, but for the disposable bio hazard ppe guys will need to wear when working on that tank.
Congrats on being a new RV owner! Enjoy it and best of luck!
Harley Ultra Classic (Geezer Glide) Rider, Retired US Army Paratrooper, fisherman, shooter. Proud to have served, proud of those that still do, or have done so with pride.
2005 National Dolphin 34'