2-3 hours - once youheead out of the park and get to boat or monorail, if your timing is off, you may wait 15-20 minutes for the next one, The figure 20 minutes or so to got TO the GF, then there is check in and wiat to be seated
Figure an 60-90 minutes for meal and paying (this can take time to get check, send it back with server, have ti returned then signed) then repeat back to MK.
If your timing is spot on 2 hours. If your timing is off more like 3