I visited Lake Tahoe in the Spring.  There is a road around the North side of
Lake Tahoe (it goes all the way around the lake) that has NO border marking
at all between Nevada and California.  You wouldn't even know you had changed
states.  The Cal-Neva Hotel sits right on the border with a line drawn down
the middle of the lobby to tell you you have crossed.  I can't think of an
easier crossing!
[Posted in FML issue 1277]