David,
I have no interest in the lexan shields, but I did want to make a suggestion about your Alaska trip. I am assuming that this is your first trip to Alaska (correct me if I'm wrong). We drove to Alaska in 2010 from Houma, Louisiana (Houma is 26 miles north of the Gulf of Mexico). Needless to say, it was a long trip.
The roads that we traveled were paved with the exception of "Top of the World Hiway" which I would definitely stay off of. Everything else was asphalt or something similar. It is the trip of a life time; we throughly enjoyed it. It was long but very infromative and the scenry was awesome.
Good luck and enjoy!
Tuga & Karen Gaidry
2012 Honda Pilot