Since no project leadership people have weighed in yet, I'll give my two cents :) I do think it would be helpful to have both the state-wide county maps like this one and county level maps, like this one I recently added for the Defiance County page for the Ohio project.
If you're only doing one statewide map for each state (or want to start with that), I'd say put them on a US FSP and the US project could link to that and each state map might end up included on the state's project page or linked in the state's list of resources.
If you're eventually going to also do all the county level maps, I'd do a FSP for each state and also included these state-wide ones there.