While flipping through some of the old modules one weekend in 2011, I noticed a few introductory notes about suggested order of play (i.e., which prior modules the GM could use to introduce the current one). With some judicious abuse of a flowcharting tool, I managed to cobble together the following loose map of the order in which GDW suggested all the modules be played.

Green boxes indicate European modules and blue boxes indicate modules set (or at least triggered) in North America. Yes, King's Ransom is off in the corner by its lonesome. Lines and arrows, obviously, indicate play order. The circles marked "GSM" and "UG" are cross-connection points because direct links into Gateway to the Spanish Main and Urban Guerilla would have made the diagram significantly uglier.

The diagram also includes the dates of each module's events. Where specific months weren't available in the published text, I've attempted to infer approximate dates from mentions of seasons or other evidence; these are denoted with tildes (~). Yes, GDW's dates do result in a few temporal improbabilities.

See also DriveThruRPG's guide to Twilight: 2000 v1 modules, available from DTRPG for free at the link. Page 24 provides a suggested map for a geographic (and thus implicitly chronological) progression of CONUS adventures, including both modules and Challenge Magazine articles.