Tell them you are a trail user and that you support the BOA responses to the Boulder County Trail Plan.
More info follows.
Boulder County has a document called the Comprehensive Plan. In it are all the guidelines and plans that officials have for the county in general. It is the tool they use to guide them when developers want to place subdivisions, mine for gravel, create industrial areas, etc. Within the plan is a trails map. This map has all of the conceptual trail corridors that the county has identified.