If you haven't already, sign up for ActiveCaptain.com and check out the charts for that area. It looks to me like the river is easily 8-10' deep at low tide, which is great, because that gets you enough depth that most keel boats won't be much of a problem. According to NOAA, the tidal swing in your area is about 2'
, depending on exactly where you'll be on the river (I picked the Ortega River at random). You've got a lot of bridges in your way, though many of them are fixed and high enough that you shouldn't have an issue. But there are a few lift bridges and bascule bridges, so getting out to the ocean may not be the easiest thing if you decide to do it more regularly.
So, the next thing I'd consider if I were in your shoes is whether this is your "it" boat, or your "for now" boat. If you're looking to learn to sail a bigger boat on bigger waters, you might want to go with a $20K boat in the 27' range and see what you like/dislike, with the intention of moving "up" in a few years. Up may not be accurate - a 27 may be perfectly fine for you, but perhaps not the one you have. You may decide that it's time to start going up and down the coast, so a shoal draft or wing is better. Or maybe your kid gets bitten by the sailing bug and you start racing, and decide a 30' fixed keel racer is better. Or...
Given the changes you're about to make, and the fact that your kid will be getting to his/her teen years and may love boating, or may hate boating (especially with you - no offense intended, I'm a parent, too), I'd hate to see you invest too much in a boat just to have life pass you by. We came close to putting in an offer on a Hunter 28.5, and that's probably where I'd start if I were in your shoes. They can be had for very reasonable prices (well within your budget), and they have a reputation for being decent boats (don't confuse them with the Hunter 28, which has been roundly panned as a horrible boat). Not great (you'll hear good and bad things about Hunters), but decent, and perfectly adequate for their intended purposes. That boat should be great for the river, and would probably get you up and down the coast provided you watch your weather windows and didn't push things. MAYBE even a hop from Miami to the Bahamas. But I suspect that, if/when the time comes to make trips like that, the 28 will be too small for you. Even a 30-32 might be too small, especially as your kid gets older.
Just my two cents!