The practice followed by all the courses is to fill tee time slots with 4 people when possible until about noon. Thus, if you call and make a tee time in the morning as a single, it is highly likely you will end up with at least two and probably 3 other players (often other singles who have called in). In the afternoon, they will do the same if demand is there, but often between noon and two or three, they get few players until twilight rates begin at 2 or 3 (time depends on time of year). Usually getting hooked up is a good thing (other players are nice to get to know), on a rare occassion it is not (one of the players is a foul-mouthed club thrower).
Most impressive course by far is Osprey Ridge (it is also the most expensive), lots of memorable holes and two of the best finishing holes you will ever see. If he is only going to play once that would be the lead choice. The Lake Buena Vista course is not used for the PGA event which takes place close to the end of October (they stopped using that one ten years ago and now use only the Palm and Magnolia, and only the Magnolia on Saturday and Sunday of the tournament). The Magnolia is very popular because it is the most known. Osprey and the Palm are the most difficult, Lake Buena Vista the easiest (none is overly difficult or easy), Magnolia the longest with widest fairways, and Eagle Pines is the shortest with lots of disaster-waiting around the greens. All courses are kept in excellent shape and are fun to play.