Yes I have run it 3 times, this year will be my 4th it is simply put one of the most amazing half marathons ever and gorgeous.

To answer your questions, the field is normally about 1500-1750 (RD told me last year he'd like to get it to 2000 in the next couple of years).  There is some congestion the first half mile but it really spreads out quick.  You park at the race finish and they shuttle you to the start, its a point to point race so no real point in parking at the start because then you would have to get back to your car.  But yes if you would like to park at the start you can plenty of places to park we park up and down that road all the time training for STG marathon.

Its mostly downhill with some huge fast miles in the middle but does end with some rollers so save some energy but you gotta take advantage of those hills.  The first 4 miles are on STG marathon course and it does have a pretty good downhill at mile 3 or so before heading into Snow Canyon park.  There is slight declines for the first 3 miles before that huge hill.  The fast miles are 4-8 though those are some flying fast downhills.  Don't be afraid to run the hills fast totally take advantage of them.  After 8 its lots of little rollers and small uphills you still see some good flats and downs even after that.  There is no real major uphills in the race just rollers.  But 3-8 are the fast miles.  I like to run  the first 8 fast and then just try and hold on, last year I set a 10k pr for the first part and then set a half marathon pr afterwords.

Thanks! Now I just need to convince the wife to let me run (she's a bit tired of races this year)