Don't bother trying to pre-schedule.
"Scheduling" only really means one thing: your ride gets calendared to be dispatched to all Uber drivers 15-20 minutes or so prior to your requested pickup time. If the driver who accepts the ride is right there (and they may well be), the most likely outcome is that you get hit with a $10 cancellation fee and have to start all over.
For a ride like that, you could just order the ride whenever you are ready to load up and go. The drivers should receive a "Long Trip Notification" that your ride request is a 45+ minutes, but they won't know where you are headed.
If I were you, I would download UZURV and use that service to schedule that ride. A long ride like that, requiring XL, is exactly what UZURV is designed to facilitate. I'd do the scheduling the day before.
With that service (which I think will cost you $3), the driver will know your pickup location, your dropoff destination, times, distance, etc. So there will be no surprises. There is also the ability to offer some "incentive" for the driver to take your request -- like $3 to cover their UZURV fee, or more if you don't get positive responses quickly..
Drivers indicate their interest in your ride, and then you have the ability to review each of their driver profiles to learn more about them, what kind of car they have, etc. Don't jump at the first driver who responds. Take your time and choose. Then you select a driver and coordinate with them. There are also meaningful consequences for drivers not showing up as scheduled, so there is some protection there.
Just be sure your ride is conducted through the Uber app. Cash rides are illegal under Florida law, and you would also be riding with zero insurance. Using the Uber app, you have $1 million insurance coverage as required by Florida law.