Hmmm. First of all, how busy the parks (there are two, Islands of Adventure and Universal Studios) will be depends on the time of year you are visiting as well as the day. We were there in December prior to Xmas and we got through both parks in 8 hours without breaking a sweat. We were at the gate at 8:30 am. Did the big rides first at Islands of Adventure then went on over to Universal. In June the year before, we spent a whole 9 hours in one park because of line ups at all the rides. A year previous to that we had the Fast Pass because we were staying at Universal Hotel and we able to see two parks in 6 hours because we did not have to wait in line. So really it depends on the time you visit.