[llimllib]

A simple upgrade to your algorithm would be bidirectional search: https://en.wikipedia.org/wiki/Bidirectional_search

This image from Norvig's AI may help explain it better than the wiki page: http://www.massey.ac.nz/~a159302/lesson3/fig03_17.gif

[mcintyre1994]

That seems like an interesting alternative to BFS, thanks.