My county is on the the state wide system. For example I can hear them fine on the Petoskey tower just fine but if I go anywhere further south I cant anymore. Petoskey is about an hour away from St.Ignace.
It's very likely what you're experiencing is a problem of affiliation. Essentially, if there is not an actual radio turned to a specific talkgroup and logged onto that specific site, then there is no reason for those repeaters to carry any of that traffic. If there is a site within your county, most of the radios will be affiliated with that site. If the next county over has their own site, and just one radio from your county is affiliated with it, then you'll be able to hear that talkgroup from that site one county over. Now, once you've driven a couple hours away, you're out of range of the original site, and maybe even an adjacent site, and the likelihood of a radio being tuned to one of your county's talkgroups drops dramatically. Hence, you don't hear any of that traffic.