Nocatee is a beautiful development that's really more of a new town. The common areas are well maintained, there's a cool waterpark, a new elementary school, and a small shopping plaza with a huge Publix, dry cleaners, yogurt shop and wings restaurant. Nocatee is between Rt 1 and A1a, the "coastal highway". It takes at least 15 minutes to get to the closest shopping centers from Nocatee (other than their little one), so know that running errands will take longer than usual. I know folks who live there and they plan their errands so they do banking, grocery shopping, etc on the same day.
We considered buying a house in Nocatee but didn't because 1) we're concerned about the resale value (we didn't know if we would live in FL more than a few years), and 2) the distance to get to everything. If you do buy there, I would buy an existing home and not new construction, as you'll be overpaying. Nocatee hasn't taken off like the master developer has hoped, and they've scaled back their projections. Nocatee is very family friendly, with social activities and playgrounds.
Northern St Johns county (which excludes St Augustine) have some of the best schools in the state. Ponte Vedra Beach has the best schools, but most Nocatee residents attend the new elementary school and Nease High School, which is also a great school. Not sure where the attend middle school, but it used to be in PVB. Other great school districts are in Fruit Cove and Switzerland, both in St Johns county.
Regarding heat and humidity - the closer you live to the beach, the more pleasant the weather. We lived <2 miles from the beach and were 5-7 degrees cooler than folks who lived inland. If you don't like months of hot, humid weather, it makes a difference!
I can recommend a great realtor who helped us buy and sell our house, as well as someone who specializes in rental properties. Let me know if you'd like their info.
I rented before buying our house, and most landlords price the rent to cover their HOA and CDD fees. I doubt you would pay for them separately.