We used to live in Sparks and I wouldn't winter in either of those parks. Bordertown sites are really close, Sparks Marina gets good reviews but it's pricey. We've stayed at Shamrock and it's really tight in there for bigger rigs too. We've stayed at Camp n Town in Carson City and liked it. When we return now we stay at Grand Sierra RV park, it has reasonable rates and you can use the hotels's amenities like gym, pool, etc. They have monthly rates all winter but not in the summer. We have friends staying monthly at the Gold Ranch right now and they like it.
Surprisingly, Reno doesn't usually get a lot of snow but it is cold, you will have to wrap your water hose with heat tape. We kept a small electric heater in the basement for the coldest nights. Also, if you have an rv frig they will freeze so you need to put a light bulb on the outside vent to keep it from freezing. Ours did freeze and we had to replace the cooling unit.
