Brett, my grandfather grew up sugaring in NH, then later in life ended up in TN.
Down there he didn't have access to a big stand of woods so he used to drive around Knoxville picking up sap with bins in the trunk to haul it to his sugarhouse. So, city trees can be good, too. Besides, Zionsville isn't that big, you just need a tank you can haul behind a lawn tractor.
We only have about 15 taps on the 20 acres my partner owns, all of the rest are on "borrowed" ground that's adjacent to his. As long as we keep an eye on it and don't cut down any trees we're free to use it. There are times it would be nice to own it, but we're OK with our current arrangement.
You never know, you may be able to find someone willing to let you use their trees in exchange for syrup, just be ready with info for them on how it doesn't damage the tree, etc.
Glad to hear about the tour, it's a lot of fun to do those. I'll have to look for the paper - good job on publicity.