Is there any way to do a 1-man campaign?

@ChrisPerkinsDnD is there any way to do a 1-man campaign in DnD? Just you and the DM type deal.

— Michael Bennett (@MikeEvenify) February 22, 2016

When I was a kid, I DM'ed games for my next-door neighbor, Dave Harris, who played multiple characters. It worked. https://t.co/XJCwuU4uul

— Christopher Perkins (@ChrisPerkinsDnD) February 22, 2016