Spent a little while today making a map showing roughly 200 mile distances. Did in by pasting screen shots of Yahoo maps into Excel then adding the circles that are roughly equal to the 200 mile range shown on the map. 6 tanks of gas to Sturgis, or 6 tanks of gas to S Florida, easy to see at least for me.
It's rough but I'm keeping a copy on my phone so I have a reference...

 

8 to West coast or 8 to East coast ?

 

From Houston Texas, looks like roughly 8 to LA or 8 to Pennsylvania. You can make your own when goofing off one day.

 

Not trying to start anything but your circles are for straight line roads, or as we say in TN "as a crow flies". Your circles may work for some of the straight roads in the west and mid-west. But when you get in to hilly to mountain terrain the roads get much more crooked you will ride many more miles than the circle indicates.

 

I don't think it's meant to be exact, but it does look like a good reference if you need to try to plan for a place to sleep while traveling.