I-10 east of San Antonio is, in my opinion, boring with the hassle of driving thru Houston. But we've tried other routes and haven't found anything much better so that's the way to go. There are some nice Texas State Park campground just north of San Antonio.
After hearing about Louisiana from people here we decided to try a couple day stop on our way back this year. It was soggy and had terrible roads and the traffic was bad too. Maybe we picked the wrong spot. We certainly picked the wrong campground.
So we just try to get by that stretch of road as quickly as can be done but you'll have to find a spot to overnight. Once you get into the Florida panhandle there are some nice campgrounds. We stopped at Eagles Landing CG in Holt and it was nice for an overnight. Blackwater River State park is in the same area and is a nice park with the CG on the river.
Once you turn down I-75 there are a number of State Parks built around big springs. All are excellent for a couple days stop. Later in the winter you have a good chance to see manatees at some of them. Manatee State Park in particular.
Take I-75 down to the Florida Turnpike and follow that to Orlando. If you want to do the beaches then take a day trip over to Daytona Beach from Orlando.