An interesting and wonderfully FREE campaign system for the ECW:
"Tinker Fox - an English Civil War campaign game of garrison warfare in the England, Scotland and Ireland, 1642-1652, using the BATTLEFINDER card system (also for use with Very Civile Actions)"
Tinker Fox uses an interesting strategic movement system which abstracts the area into key areas. This allows you to do away with detailed map movements (and get on the with the business of dispatching those rebellious Roundheads!).
Pretty neat. I would also consider going further and 'cut' some of the linkages between sections (for deep river etc) to make strategic chokepoints.
One can see this interesting system (with tactical games resolves with a C&C variant). Very interesting with some nice ideas for Campaigning
Alternatively, the Napoleonic rules "Blucher" include a short campaign system which would also give an interesting game with less preparation required: