It isn't difficult to pick a starting point & decide on a 10 - 15 mi route. Pick your favorite roads or coordinate with the ride leader of the longer ride. Leading has the benefits of picking starting point, route, distance & minimum speed. I'll even give you a map program. CZ leaders are in short supply.
Thought I'd skip July so some other people have a chance. Perhaps they have some favorite roads that we're missing. I'm happy to make a map for any CZ ride. I like making maps.