Across the sea of stars
You might be interested in
Interstellar Migration and the Human Experience, (ed. Ben R. Finney and Eric M. Jones, Berkeley: Univ. of Calif. Press. )
which covers this topic in some detail. It considers (among others) the Polynesian voyagers who used a Neolithic technology to explore and settle a vast and hostile environment, the Pacific Basin, as a model for future human expansion into the galaxy. It's a classic, a bit dated, but has many insights you might find valuable.