Like you, we have just made an attempt at a longer-term road maintenance plan. Our window is a more modest five year plan, as we felt it was about all we could manage, starting from nothing. We're in Cumberland County and have consulted with the Cumberland County Soil and Water Conservation District. They told us that they could prepare a road maintenance plan for us and gave us a sample document to give us a sense of the final product.
We would love to have the CCSWCD prepare a plan, but the estimate for doing so was likely to be $3,000 or more (in part because our road is 1.5 miles), so we've opted to prepare several spreadsheets that lay out (1) repair projects by year, (2) culvert, drainage ditch and catch/drop pool cyclical leaf and weed cleaning and (3) a sediment check and removal schedule. We're also using a blog to document our projects as we undertake them, with a description as before and after pictures.
It is our hope that we might eventually be able to afford a CCSWCD road maintenance plan. You might check with your local conservation district (if you have one) or even with ours to see if they might share/print a sample plan for you. Seems as if that, plus access to the individual noted in an earlier response to your posting, might be a good start to your efforts.