We went to Buelton last weekend so our kids could attend a BMX Bike Race. We had stayed at Flying Flags once before about a year and a half ago, but it was just a stop over and we didn't stay long enough to really use the facilities. And is was November at the time so the pool was shut down.
The park seems to be very kid friendly, important for us. They have recently installed new playground equpiment and the kids loved it. They have huge areas for tent campers that goes largly unused, so the kids have plenty of room to run around or fly a kite. The pool was open and heated, the kids had a great time, but being that there were so many kids there this weekend, I didn't hazard into the pool myself
They also have an adults only indoor hot tub. So even when the kids are out in full force, you have somewhere to retreat to. They also have a game room with several video games and a pool table available.
The onsite store is small, but seems to have most emergency type supplies, and you're right in the town of Buelton so anything else you might need is not far away. There is also a Pea Soup Andersons and a couple of other restaurants within easy walking distance.
Our campsite was fairly level, only mild leveling was required. Shade trees on many spaces. The spaces are a little closer together than I like, but there is still room to put out the awning. A full hookup site cost $28.50 per night, and they have surcharges for more than 2 people and dogs.
Overall, a nice park. We will visit again.