While I don't have 30 some years of sailing and boating experience I do live in MN which has some nice lakes to sail on. I bought my boat 24' Westwind six years ago and have been hooked ever since, even though I have been refitting her the last three summers. I noted that you are planning on sailing on Lake Lanier in Atlanta. Now I have never been to Alanta, much less Lake Lanier but I note that the lake is a reservoir about eight miles or so from the dam to Browns Bridge Road, The majority of the lake being about two to three miles wide. This is a little smaller then Lake Mille Lacs where I do most of my sailing.
I am going to suggest that you look for a boat on the smaller end of your range. My experience has been that:
1) Smaller boats are easier to tow behind your truck (mines about 7000 lb with trailer and boat and gear).
2) Because you can trailer your boat without having a semi pull it makes it much more likely you will make it to the coast with your boat. In my case taking my boat from Mille Lacs Lake to Lake Superior.
3) The slip fees are less.
4) All those things you didn't know about maintenance and repair
of a boat increase exponentially in complexity and cost with the waterline. Best to start out a little smaller and enjoy more sailing in the beginning.
5) There are a lot of good small boats on the market and they are cheap. I paid $4000 for mine which included a two axle trailer with an 9.9hp outboard motor. I figure the motor for $700 and the trailer for $2500 which leaves $800 for the boat. Which came by the way with four good sails and was in very good shape, until the unfortunate incident with the dock which is another story.