[baddox]

> I can't think of anywhere else in the US where a cyclist could a century ride without having to deal with automobiles.

I assume you mean in or near cities. There are several long-distance bike-only trails (that I know of) in the US, but they tend to be in protected nature areas.

[dalke]

The 185 mile long Chesapeake & Ohio Canal bike path connects to the 150 Great Allegheny Passage bike path, giving a 335 mile long bike-only trail between D.C. and Pittsburgh.