Hello - I have the same general question (and agreed, CarPlay doesn't actually start the navigation, but it takes a lot of time to calculate a route to a location that I don't necessarily want to visit yet) - the point is, how do we disable the "auto-calculating route" feature?
I am really trying to like CarPlay (Ford Sync3 in the FFEP, iOS 10.2b4, iPhone 7+, AT&T) and this is one of the many little things that makes me keep going back to Sync3 (which is a surprisingly good platform). I have been focusing my time mostly with the maps experience.
I would suggest the Apple folks incorporate a few ideas from the Sync3 full screen maps view. Small details like showing the speed limit, the current road I'm on, what song is playing, etc. are some of the missing things that (currently) make Sync3 a better experience.
(I won't comment on the quality of the maps themselves; my point here is about the user experience of the system. Apple's CarPlay Maps is too sparse at the moment, with only a few POI integrations like Yelp and OpenTable; I'd like more general, basic info shown.)