> I'm thinking about what to do around street length & difficulty

Here's one idea if it might help you get started (though you can polish it):

- Mark all "dead ends".

- Mark all private streets.

- Recursively (or perhaps I should say iteratively, depending on your POV) mark all roads as X that only lead to previously-marked roads.

- Non-recursively, unmark each marked road that is both adjacent to an unmarked road AND that satisfies some reasonable heuristic (such as "being within 2 intersections of the center of your circle").

- Also unmark all freeways/highways/expressways/other reasonably-major roads (although few if any of them should be marked at this point)

- Delete all marked roads from your list of candidates.

This should ensure that every candidate road actually has a non-negligible chance of being at least seen by random drivers, and not just by residents who are forced to drive on it on the way home.

You can obviously augment

OK thanks but I do need to compute all of this. Plus some roads are broken into a lot of segments so I have to do more work first in finding & joining them up. Hopefully I could do all of it but just saying, it might be too much.