Speaking of Lake Ann, there is the Chain of Lakes trail system over on Reynolds Rd that has some pretty rough hills. I used to spend a lot of time out there running and XC skiing.
Nothing in the near future, but you can keep checking here: http://www.costco.com/new-locations.html
From a facebook thread I ran across from 2013, they recommended calling in and asking for Costco to bring a store to TC: 630-581-6200
https://www.alltrails.com/us/michigan/traverse-city - This will give you a great list and reviews. There are a lot of lesser known trails in the area.
You likely won’t have a ton of luck with a top of set antenna but a bigger arial works great. I have a cheap Amazon antenna (this one. ) in the Attic of my garage near town and I get something like 45 channels. I get good solid signals from all the major networks you mentioned and a few others including some duplicates of the major networks. Most TV towers in the area are just north of kalkaska, so point your antenna that way.
Of course! I'm using the CarproCam. Got it for Christmas actually! I didn't pick it out, but I agree that it does have good video quality, especially for night. Probably the only feature I wish it had was GPS for location and speed, but that would probably cost a lot more.
One thing to note is I'm actually have a lot of freezing issues with it though so I can't recommend it yet. Hopefully I just got a defective one. More than 50% of the time it freezes when it turns on so I haven't been able to trust it :/