Why ride across the continent? (part 1)

When I was in 6th grade, my family took a tent, clothes, grill and a trailer and camped across the country.  One day in Kentucky (if I remember correctly) we met two guys who were doing a cross country ride.  They had panniers in front and back and were carrying their tent, clothes, a small stove--basically a very small version of everything we had in our trailer.  The next day, we did some sight seeing, travelled a little, and got to another camp site.  Shortly after we set up our tent, the same two guys rode in.  I was impressed that they rode, with all that stuff, as far as we had driven.  Ever since then, I've thought it would be fun to do it myself.