It's hard to avoid Orlando when Astor is due north of the city. You could go west and pick up 441 in Ocala but that makes sense only if your time is not that important to you. The I-4->FTP->441 route really looks like the most direct way, the FHP section is short and the toll should be minimal. We ran all the way down the FHP from I-75 to where it ends in Homestead on the way to Marathon Key and the tolls weren't that much and we were towing our fiver. The time and distance saved made it worth while to us.
US27 used to be a good route south of Orlando but the Sebring area buildup ruined that path.