We were at the St. John Race last year - first timers and it was a blast. If I were younger. . . . .
The place is designed for RV camping (all boondocking) two areas, a smaller quiet area where quiet hours apply and a much larger "party" area. Get there the early the day before, they provide free shuttles to town to meet the racers and check out the boat. Then get up early race day and send someone to secure your place in line. Getting in early and you can get your choice of places to sit (bring chairs, blankets, coolers, hats or sun shades, etc) and then enjoy the races.
St. John's is really in the middle of nowhere so I suggest you bring everything that you will want (food, beer, etc.) If it's warm you will be running your genny all day for the AC so make sure you have the fuel for that.
Steven and Stephanie
2007 Winnebago Adventurer 38J
2008 Hyundai Elantra