cheappc.....I believe two strokes can go almost anywhere until 2012 (EPA ruling) After that, I think two strokes are still permitted in certain areas so long as they meet 2012 EPA emission requirements, but for now I think you are fine and legal.
I was just there in May, and saw plenty of 2 stroke jet-skis all over the place, so I conclude by that that you would be fine.
Lake Havasu city (the resort and launch, is in AZ, the other side of the lake is in California waters, you will see police from both states patrolling the waters, they are used to people being there to party, so you can enjoy yourself, but, like most places, you must remain responsible and in control of your vessel....If you don't get stupid you will be just fine.
If you go, make sure you take a few hours and drop anchor in "Copper Canyon",... it's an infamous place known for packing lots of boats all rafting together, creating a a boat hopping party barge, loud music, naked girls and guys climbing up and diving off this jagged rock cliff(which the park authority has installed a 1-1/2 diameter rope pull up the side of the cliff so they don't fall while climbing)...you can hang there, absorb the atmosphere, meet some folks, maybe down a couple of beers all while watching crazies shed their clothes, climb a granite cliff, look down to the cheering crowd, who likes to rate the dives on a 1-10 scale...then do their dives..Even for an old guy like me, this place was very cool, On the way back from Copper Canyon, slide your boat onto the white sands shore outside the Naked Turtle Restaurant, for some burgers and brew...lots of boats, fun and action everywhere you look. In the evening we took the boat up and down the main channel, idle speed, music playing, cruising beneath The London Bridge was cool..seeing hundreds of really nice boats all nosed into the sand along the shore under the stars, like some nocturnal boat show party (with loud music playing from everywhere) was even cooler....You may not get the best nights sleep in this town, it's one giant party...but you will have a blast, (and you can always get caught up on sleeping when you get home)...Let me know if your planning a trip, I am ready to go again, the friends we took along want to make this an anual trip instead of the Lake Powell House boat thing..who knows...just might see you there. Take care, John