We went ahead and made reservations at O'Leno State Park, which looks like it's not too far off I-75 between Lake City and Gainesville, so we'll be able to plug in and turn on the air conditioner and open the slides and get some sleep. We won't be as close as Lake Louisa, but will be able to travel more than halfway from home after work on Wednesday night and won't have as far to travel on our check-in day (Thursday, May 11). We originally planned to drive all day Thursday and not get to FW until late afternoon/early evening, until I saw all the recommendations on here about arriving early for the best chance of getting a better site assignment. I like knowing we'll actually get there in time to enjoy the fort on check-in day instead of getting there late and going straight to 2 days in a row in the parks without getting to explore the Fort. Thanks for all the suggestions!