Here is what I allow to get to the front gate. This includes traveling, parking etc. (We usually stay at Windsor Palms or Emerald Island, but the timing is pretty much the same, perhaps a minute or two different!)
To Seaworld I allow 25 mins. (Driving time is approx 15 mins, plus time to park, walk to the entrance etc)
To Universal I allow 40-45 minutes. (Driving time is approx 25 mins, but it does take time to get from the parking structure to the front gate)
Both places offer preferred parking which, if you are arriving early, is not really worth it. You don't save much in time or distance.
I like to get there for opening too, and using that timing means we don't have to rush. We do have to be prompt leaving (and you know how long it takes to get out of the house sometimes!!!). It does help to have all your stuff prepared the night before.
Have a great time. I wish I were going!
--Kay