Thanks for the compliments!
We got THOSE stickers straight from the Sandy Lion Sticker Warehouse (which is 10 minutes from my home) but they are just the same stickers you get for bedroom and playroom walls at
Walmart/home depot etc etc).
We lost a couple of the smaller ones on the trip, but the big ones were solid.
To apply them we just used soapy water on the area we wanted to apply the sticker, placed it, adjusted it to where we needed it, and then used a credit card to squeegee out the water to seal it. To remove them at the end of the trip we just peeled them off.
The markers are Crayola Window Markers. Due to the tinting, we had to apply on the outside, and we hit a rain storm 6 hours into our drive and it all washed off.. (not that that was a problem i just quickly re-did it).
This year our theme is mischief makers. (Stitch, Lotso, Donald Duck, Pluto)

as well as a custom 25X25 inch hood decal (art provided by the fine folks on the diSign boards!).
I will post pics once it is complete!