Parker is one of my favorite destinations although I don't get out there as often as I used to. Keep in mind it slows down big time after Labor Day so the party scene will have died down. Here are the must-do's in no specific order:
1. Cruise through the Keys and check out the houses. The South entrance is on the AZ side about 2 miles up from the public ramp.
2. Stop at Badenochs for a meal during the day.
3. Have a road raper at Road Runner. This will kick your butt so make sure you have a sober driver. Road Runner is the party spot at night so round up a crew from the event and take the boat up any time after 9.
4. If you're looking for a more relaxed scene, go to Foxes a few miles up river. They make the best mudslides in the lower 48 states with crushed up reeses peanut butter cups...so good! It's more of a locals hang out but be cool with everybody, don't cause trouble and you'll fit right in.
5. The only good restaurants IMO are the Blue Water (restaurant or Cantina) or Strokes up river. Strokes is off the water but the steaks are excellent.
6. The Desert Bar is an interesting experience. Worth checking out if you want to get off the water for a while especially if the weather cools down.
IMPORTANT - Parker is a great place for night time boat cruises and partying. Be careful, have a sober driver, keep an eye on the shorelines, and go slow!