When I was a kid I was into Estes model rockets and it always amazed me the preferred/documented way of glomming the multiple stages of engines together was a single strip of scotch tape.
My memory is that two-stage rockets had a few more points of failure but were harder to retrieve, so not really worth the effort. The Estes engines solved most of the technical challenges, but I lived in an area with lots of trees and no huge expanses of open space.
