TOD - The longest drive, all in one stretch, was in 1959 when my parents and I made our first trip back to Portland, OR, from Detroit. We drove through from Denver to Pendleton, OR, with Mom and Dad sharing the driving. It was about 1000 miles and the interstate highway system was just being built. I remember my mom was driving when we went through Cheyenne, WY, and we were listening to a rodeo on the radio (sounds like a title for a BK novel, doesn't it?) when we passed the arena where it was taking place.
While our DS Rob was growing up, our family took 3 long road trips. Our "See the USA" tour in 1996 took us 3 and a half weeks, about 6000 miles, with these major stops:
Black Hills, SD
Yellowstone National Park
Salt Lake City, UT
Zion National Park
Las Vegas, NV
Los Angeles, CA
Phoenix, AZ (where picked up my mom)
Albuquerque/Santa Fe, NM
Amarillo, TX (you're right, DR Jose - ugly)
Tulsa, OK
St. Louis, MO
"See the USA II" in 1999 took us east to many Civil War battlefields, Washington, DC, and the Jersey shore and NYC.
"Colorado, Rocky Mountain High," in 2001, took us to the western state we had skirted around in 1996. On the way out we stopped in Independence, MO, at the Truman presidential site and on the way back in Abilene, KS, for Eisenhower.
We loved these trips. I think everyone should drive cross-country at least once in their lifetime.
Long walks I remember were in Chicago (not this most recent trip).
I'm not much of a bicycler, but we have done pieces (maybe 10 miles or so at a stretch) of some the Little Miami Trail, which goes from Cincinnati to Dayton.