It is easy to get around Universal by car so not staying right on site is not a huge issue. Many of the area hotels have shuttles. If he is a HP fan...get a park hopper ticket to both parks, there is a HP land in each of the two Universal parks.
If you are just going for a day or a short trip, spring for the front of the line pass...we did one of the parks in half a day and hit all the major rides and were ready to leave by early afternoon.