Hi, Lisa!
As long as you choose just one park for your first 3
FastPass+ selections, it can be wherever you want! I think your plan of using your FastPass+ for later in the day is a great idea.
My family likes to get to the parks when they open. This is when the parks are the least crowded, and we can really zoom around and enjoy a bunch of attractions with short wait times. We then head back to our resort for some down-time at the pool, then head to a second park for the afternoon. We don't rush as we know we have those magical FastPass+ times waiting for us. That is the best feeling!
Remember that after you use your last FastPass+ you can book an additional "rolling" FastPass+ either on your smart phone's
My Disney Experience app or at a kiosk in the park. This rolling FastPass+ does NOT need to be in the same park as your initial 3 selections. Times and attractions are based on availability, so you will need to be flexible when getting those rolling FastPasses.
In addition to your FastPass+ bookings, make sure to book your
Disney dining reservations. Coordinate your dining with your FastPass+ schedule for a seamless day and night of magical fun!
Cathy