This is a rather surprisingly nice RV park at the Napa Valley EXPO, basically the county fairgrounds! http://www.napavalleyexpo.com/f-rvs.html
There are some back-in sites, but most are very large pull-throughs. Roads are asphalt and the sites themselves are cement, with full hookups at each site. No tents or screen houses are allowed, and pets are limited to three per unit. No pet enclosures or grooming outdoors is allowed either. No scooters or roller blades, but bikes are allowed. No cable tv, but there is free WiFi. No fire pits or grills. Costs are fairly expensive at $45 per night with the Good Sam discount, but after all, this IS Napa, where an ordinary hotel room costs $250+.
Big advantages of this RV park is that it is really almost the only option for quite a few miles around, plus it is within walking distance of downtown Napa and the riverfront area, the wine train, and a very nice farmers' market, the Oxbow Public Market. This latter place has a farmers' market, food booths, and a lot of little food shops and restaurants where you can get a sandwich or a full meal. http://oxbowpublicmarket.com/ One of my favorite Napa places is a little farther away, maybe 7-8 blocks' walk, but well worth a hike: Shackford's Kitchen supplies.
If you like trains, the local model railroad club is open for visitors a couple of Friday evenings each month right at the fairgrounds. My grandkids always enjoy visiting that, and last Friday we were the only visitors, so kids got to ask a lot of questions and got to ask them to run specific trains. They also got to meet a couple of the wine train engineers. There is also a very interesting little store in the fairgrounds that sells fermentation supplies to wine makers. So if you need a couple of hundred corks or some yeast, or even a press and storage vats for home wine making, this is the place to go! http://www.napafermentation.com/ They even have supplies for making your own olive oil, beer, cheese or yoghurt. It is open 6 days a week and fun to explore.
For an RV park almost in downtown, it is pretty quiet, except when there is something going on at the fairgrounds, like the bingo club or those noisy seniors! There are two sets of camp hosts, and the place is very clean and well-taken care of. Here are some photos. Note the animal barns in the second and third photo!