Dont let these guys talk you out of your trip. Parker does get rough the peak part fo the day being mid day to about 3-4pm. you will be fine in the mornig and late after noon early evenng. I ran my 18' spectra for a couple years there with no porblems, and we have been running our 19' ski nautique for the past 15 years there with no problems (it does get a little rough sometimes, but we have yet to sink a boat). dont exepct flat glass water, unless you get up at the crack of dawn.
The lower sandbar is always a good time. The must sees are Foxes and Roadrunner. And the upper sandbar (Accross from Foxes) is always a good time too.
As far as noise goes....make sure you are running water through your pipes and inserts if you have them. As long as you dont drive around all day raising hell and at least show you are trying to not be loud, you shouldnt have any problems with the popo.