People of Rhode Island, where were you? Do you not travel? Get up, get out you lazy so-and-sos, and let's see you on the road! Very disappointing indeed. The same goes for those slackers in Wyoming. And New Mexico. I mean come on! Niagara Falls isn't that far away is it? Pffffff.
By far the best way to keep children amused on the road in the US is to play the licence plate game, the object being to collect the lot. You could do some fairly hardcore variations on this, as each State has loads of different styles of plate, including a fair few with birds on, which were of course my favourite.
My parents engaged me on a trip back in the late 80s, and I've now done the same to mine. Back then, on a six week trip starting in California and doing a massive loop up north into Canada, across and then back down via Montana and Wyoming (so annoying), Utah, Arizona, Nevada and home, we got the lot, including Hawaii and Alaska. This time around, even though it was Memorial Day Weekend, and even though we went to the tourist hotspot of Niagara Falls, we topped out at 44 - the missing being Hawaii and Alaska, as well as Wyoming, New Mexico, Rhode Island and one other, which we think was Colorado, but our collective memories are, six weeks down the line, failing miserably. This is pretty good in a mere six days, but we did work it hard, including cruising round car parks, stopping at rest areas to check out the trucks, and generally taking it way too seriously. The below is a composite of a few that I snapped in a random car park, including our first Louisiana just as all hope was fading. Of course once we got to my Grandma's in Ohio, what should be parked two doors down......?