What a day! Based on local recommendations, I took a loop route (map) which made for a long (15 hours) day in the saddle. It started raining just before I entered the park through the western entrance, and continued until I got to the eastern entrance. The first 9 miles of park road were just mud, and I was getting hit by waves (up to my hips) of muddy water from oncoming vehicles. I am sooo glad I was on my Honda Africa Twin, which made it through with only a little slipping and sliding.
The park itself is beautiful and the Going-To-The-Sun road are a great driving experience in good weather. It was raining, but I used Google Maps StreetView to get some sample shots.
After I left the park the sun finally came out, so I turned around and drove back through the park until I caught up with the rain. I then turned around and drove out of the park and finally got to enjoy the spectacular views.