It sounds like you would love a community like La Costa Valley. Great schools, close to the beach, shopping, entertainment, etc. and you get all the amenities (2 pools, tennis, fitness center, walking trails, etc.) for $100/month as an HOA fee. Mello Roos is about $700/year. The High School is either La Costa Canyon, San Dieguito Academy, or Canyon Crest which is down in Carmel Valley. Can’t go wrong with either.
The community was built between about 1998 and 2003 and it’s very family centered. You’ll find the occasional senior citizens walking in the morning, but it’s mostly families with the kids at home. You might try renting for a while before buying. Prices may come down and if you walk the community you’ll get an idea of which neighborhoods suit your needs. Many of the neigborhoods have almost a “college football tailgate feel” to them with the neighbors throwing outdoor parties together for Halloween, 4th of July, etc. If you have a dog, I’d encourage you to drive over there on a weekend and go for some walks in the different areas to get a feel for it.
There are also some slighlty older communities near LCC High School (just across Rancho Santa Fe Road) which are a little more affordable (and a couple that are more expensive). They don’t have the same amenities, but they are closer to Stagecoach Park which has Jazz concerts every summer and has great athletic fields.