Wow, lots of great responses. Thanks for all the helpful input.
Lots of votes for small boat/small lake, and lots more for big boat/big lake. Sounds like you can't go wrong either way. My inclination is to pick up a cheap used small boat and sail it like crazy for a couple seasons. I could probably sell it easily and not lose much when I decide to move up to the big lake boat.
I'm mainly reluctant about buying a bigger boat in the hopes that I can consistently dock it single-handed. A smaller boat is probably a lot more forgiving at the dock. If I get really good at docking a smaller boat smoothly, I'm hoping that stepping up to something line a 27' boat will be an easy transition.
More ideas on a smaller (not too small) daysailer that's easy to find cheap are always welcome. I'm seeing some 22' Tanzers, Catalinas and Hunters that look intriguing. I'm assuming a boat that size would be a lot more manageable both at the dock and under sail than a 27-footer.QUOTE]
I think you should try the small lake with a small day sailor. Get good at that then move up to the big lake bigger boat. I think you want to get your sailing skills down so they are second nature, then move up.
I single my 34 and the hardest part of all is the docking followed by undocking. If there is little wind, no problem, but add some wind and things get not only difficult, but stressful with the worry of damaging someone elses boat in the process. Trying to dock a big boat in very windy conditions is like driving a car on black ice. You have little stopping (wind blowing bow off) and steering power.