Unfortunately, New Port Richey and Port Richey do not have any state parks that offer RV sites...at least none that I am aware of, and I've been here for 33 years. There are numerous trailer parks that you could look into, the problem is that most of them are retirement communities and won't have much for the kids to do. I've driven by this one
http://www.suncoastrvresort.com/pages/1/index.htm
many, many, MANY times and it always looks nice and friendly and very shady (important for Florida in the summer) and it is right in the middle of everything, so it's convenient to anyplace you might want to go. I have never stayed at this campground, but it's been there since I was child and I'm well into my 30's now. One issue might be traffic noise since it is very near the main drag, but if you got a site further back, it probably wouldn't be too bad.
If I can answer any questions, I'd be happy to comment on the thriving metropolis that is Port Richey!
Stacie