Justin Walker submitted this 500+ mile road route.  For an FKT across the state any route would be allowed.  Here's what Walker did:

Also known as the Carpathian Arch, this is a 2000 km route that runs the length of the Carpathian Mountains, between Orszów (Romania) and Bratislava (Slovakia).  The route & previous crossings are listed here:  http://lukaszsupergan.com/kto-kiedy-jak-dlugo-statystyka-lista-przejsc-luku-karpat/

The American Discovery Trail stretches 4900 miles across the USA, from Point Reyes National Seashore on the Pacific in California to Cape Henlopen State Park on the Atlantic in Delaware.  In the mid-section of the country, between Colorado and Ohio, there are 2 branches of the trail - north and south.

The ADT Website describes it as follows:

Jakub Sliacan submitted the route: