Only in the loosest possible sense. Having the same (or similar, or related) characters does not necessarily imply a "full rich series". The Baroque cycle, sure, because the characters share arcs. Cryptonomicon is a completely different story though.
Stephenson said this about the relationship between Cryptonomicon and its different-timeline "sequels" (not yet written at this point): " I'm trying not to give the idea that it's a tightly locked together set of books... There are always a few strange little corners of the story that may not make sense outside of the context of the full series, but 99% of it can stand on its own reasonably well, I hope."