The local orchard around here (Fishkill Farms in NY) that has good variety has a cidery. I believe it's a good business. They're a you-pick with a big store, so they focus on foot traffic.
It looks like you've got a similar situation, being a day trip from a major city. You might even try reaching out.
If you're considering new varieties, golden russet and porter's perfection both make some fantastic cider. Golden russet is tip bearing, but otherwise they're pretty easy to grown around here. I like the russet sweeter, and the porter's is good dry.
Regarding commercial back sweetening, I'd consider filtering and sorbate. At home, I like unfermentable sweeteners, but farm stand customers probably don't want "diet" cider. I'm not that familiar with commercial cider methods though.
Have you checked with your local extension? They probably even have materials to help with a business plan.
exit: I just realized you said back sweetening AND bottle carbing. As I'm sure you know, these conflict a bit. Options are pasteurization and non-fermentable sweeteners. I think most sweet sparkling cider is bottled already carbonated, similar to beer. Some people pasturize at home, but there are issues with the process as a commercial endeavor.
