Oh, and I wanted to say that I favor the regional boards rather than county boards, just because they are more ambiguous. Yes, more people will live on the edge of a region and wonder which group to be involved with, but look at it from the approach from someone on the "outside".
I would want to live somewhere in the Lakes region, with a view of some mountains. I have no idea which county I would want to live in. Within the Lakes region, there is probably more than one county that would suit me, and I would want to weigh the differences. Some of those differences will be caused directly by the local governments. So having groups that span counties would be useful.
And yes, some people "in the middle" (or on the edges, depending on your point of view) may join more than one group. Great -- that will help the different groups to work together better.