I agree that it is very important to do the majority of the cleaning before I go. I also spend alot of time in the cockpit area and under hood as I don't want to do much cleaning on that once I get there.
However, once I do get there, I wipe the entire car down with Final Inspection. We do another clean of the windshield with windex to take off any bugs we accumlated along the way. I also had to check under the hood as bugs collect there after their demise of going through the radiator and through a fan, then deposited under the hood. Then, we lay out all of our stuff and set up the seat belts in cockpit making sure the steering wheel is straight, etc.
Lastly, we foamed all the tires and cleaned wheels. And, make a quick walk around the car to ensure we didn't miss anything in our cleaning at the garage before we left.
At World of Wheels, a totally different approach is used. Two weeks before WOW, the car went up on the rack to clean, inspect, and touch up everything underneath. It does not leave the rack until the bottom looked brand new. Once we got to the show, we did a overall clean just before the show began. As well, we took along a floor jack to index the tires so the BF Goodrich was up and T/A Radials are down. The GT hubcaps were also all facing straight up.
This all seems alittle over the top, but, we had some success in most all shows. Zach was always a great help and worked hard to prep the car and keep it in show condition throughout a show. In my opinion, and as I have judged several events, almost everyone has a nice car. What distinguishes a 2nd from a 1st place is almost always cleanliness. As a judge, I almost always approached the class I was judging that if someone was unwilling to really clean the car, they moved to the bottom of the list.
Just some random thoughts.
Paul