If you knock on doors and are courteous you will eventually find land to hunt on. I don't though. I actually enjoy the challenge of hunting State Land.
The DNR "where can I hunt" web page. There are some options to hunt private lands listed. HAP (Hunter Access Program) & Commercial Forest Property are hunted less than the state game areas. Each has a link to specifics on the web page link below. MI HUNT is a good tool to find the little squares of state land that are not listed on the game area maps.
The Ruffle Grouse Society has several hundred acres of property south of Gun Lake listed in the Comercial Forest properties. I hunted it a few years ago and never ran into anyone. If your options leave you hunting state land I would encourage you to pick up Bow Hunting. The woods are much quieter during BOW season and it's warmer!!! Though last years Bow opener seemed busier than the Gun opener was
http://www.michigan.gov/dnr/0,4570,7-15 ... --,00.html