I helped install the first packet networks in the Harrisburg PA area years ago, so I think I can see several things - quite apart from the technical aspects of using Winlink - that need to be considered before you proceed.
First off is frequency coordination. I would touch base with TMARC and see if there will be any issues with the frequencies you wish to use. Remember the rules about coordinated vs. uncoordinated users.
TMARC Home
Next up - check the beta site user lists and see if there are any Winlink users already in the area. Be sure to click on the 'RMS List' tab
http://www.winlink.org:8995/RMSChannels
I thought I did see one or two users on the Eastern Shore...these folks will likely be very valuable to you in order to answer your questions about the network specifics. They should, at the very least, be able to point you in the right direction.
Next on the list is getting the various sites cleared with the county commissioners - assuming here you wish to use county property, and not just other users - including all the proposed construction details, purposes, equipment, estimated costs,
insurance and several other factors. No doubt I've forgotten quite a few other things you will need to supply - and that will need to come from the commissioners or someone they would appoint. Be ready to give a very detailed dog and pony on the benefits, usage and - no big surprise here - costs. Insurance is a huge issue that probably could use a separate discussion all its own. I was not involved in that side of things, but from the discussions, at least at the time, it was a pretty big deal.
I'm sure others will chime in here at some point, but these are pretty decent starting points, I think...
GL with your project...Mike