It is still quite possible to have fun when the park is packed, you just have to do it right. Im assuming you have a Maxx Pass, if everyone else in your group does too that means that you can enter an hour before the park opens (huge plus) but either way here are some basic rules to follow:
-Park in the Soak City Lot. That way you will enter at the Magnum entrance, and means you will be much closer to TTD, MF, and Maverick then the Main entrance. To get to the SS parking lot, be in the far left lane at the parking booths, and continue up the Perimeter Road or if you are in another lane put your left turn sign on for the first parking attendant after you pay. Either way, also check to see if Maverick is running (if you are able to do early entry.)
-The key to hitting most of the big rides is to hit them early, if you are able to be there for early entry get there early (30 min before) so you are somewhat near the front of the line. If you saw Maverick testing when you drove by it head there first and ride, if you didnt, go to MF and ride, try to do the ride you didnt do next then head to TTD to get that one out of the way when the park opens.
-If you cant use early entry, then save Maverick for later (it already has and will have for the rest of the day a 105 min wait) and try to do TTD (assuming it opens on time) first, otherwise hit MF.
-Dont do Raptor until the late afternoon, it has its biggest lines in the morning.
-Check what time the indoor houses open, and be sure to be at one (I suggest either Pharoh's or Vampire since you can easily knock off these two back to back with minimal waits) 15 before opening before the line forms
-If you are going to do Werewolf Canyon (and again, if its windy dont bother, if it isnt its pretty cool) get there 60-45 min before opening and queue up, trust me youll be happy because by the time it opens the wait will be 2+ hours long
-Fright Zone and Fear Faire are scare zones and thus have no lines. They are also the best haunted attractions ride "early and often"
-Since you wisely choose to park in Soak City, you can take advantage on the tail end of the night too. Magnum during the last 30 min the park is open is usually close to a walk on and at the worst a 15 min wait. You should be able to marathon the sucker at least 3 times before the park closes for an amazing cap to your day.