R.G.
being new to the same area (we moved here last summer) this is what I've found out already... for really good pediatricians,optometrists,and dentists that will work with your insurance get on-line to San Diego's Rady's Children's Hospital.... and look for where it says recommendations, you can give them your insurance information (what type of insurance you have for them), they then will email you back with lists of these services in our area who not only take your insurance but are also affliated with the hospital, a lot of times that means that they do rounds at the hospital and the after hours nurse line is the hospital.. we personally take our son to the Children's Medical Group in San Marcos, which is just into San Marcos from our area, they are the best... especially Dr. Gina Rosenfield.
Now dentists, there are all kinds of Pediatric dentists in the area... we personally take our son to Children's Primary Dental Group on Rancho Santa Fe Road, again just into San Marcos... (by the way I mention these places because both of these places virtually work with any and all insurances from medi-cal, healthy families, etc... not many places in our area are willing to work with medi-cal, healthy families is a little better to find places willing to take them to...
but these places are also top notch and again work strictly with children, both are also recommended by the Children's Hospital)
seeing as how your in the Aviara area... they're is actually a really great park over in that area, and I believe it's actually called the Aviara Park... it's essentially next to the school but maybe two more blocks passed... it's a beautiful park and you won't have to worry about sand...it's built with the cushy foam stuff...
also, heading into Encinitas, there is Moonlight beach off of B street and they too have a really nice park and it's also the beach... parking can be a little short sometimes because it is a famous beach... but you can usually always find something.
Another good beach that you can also park on the beach is So. Carlsbad state beach...
also, when walking into the grocery store where they have the free magazines.. look for the Family magazine-it's free... but it does hold a lot of good information in it, and it's for the county of San Diego... with information on what to do in the area and in general just tons of good stuff... lot's of advertising.. but all generally geared for kids... which could possibly give you even more ideas on things to do and what not...
well hoped this helps a little...