@Traster...
Here's the skinny - avoid places like Meijer's, Kroger or anyplace that has a license to sell liquor, including the corner party store or 7-11 & even some gas stations! If you must drive some where, make sure if you are OCing to disarm PRIOR to getting in the vehicle. Here's where it gets really tricky - MI courts have ruled that ALL of the car is fair game when it comes to police (shady) ones anyway, charging someone. This means that technically a person can be charged for simply setting their holstered pistol in their trunk while getting ready to put it in their gun case after unloading it and going into transport mode WITHOUT a CPL.
To avoid this, keep your case in a easy to reach area of the trunk and avoid letting the pistol cross the boundary of the trunk. Use your weak hand to get it, that will help keep the pistol away. Once you have the case, place it on the ground (not the bumper/hood/roof/tailgate...as it is IN the car according to the courts and now you have committed a crime).
It sounds nutty (as law often is) but with practice it can be done safely & quickly. Remember it must be completely unloaded (no round in chamber/cylinder). The good thing is you can keep your mags/speed loaders with you so when you need to go back into legal OC carry mode it is pretty easy.
Take the Q or another OCer up on their offers to meet up and give you advice. It will make things much easier and comfortable for you when you are ready to start carrying. Attended one of the FREE OC seminars that MOC (Michigan Open Carry) does. Get as much practice as you can before you carry. Learning in a oh crap self defense situation is never a good idea.
Be safe and know the law inside & out before you carry! Why? Police are the only citizens that can use the defense of being ignorant of the laws and get away with it.
PS - MI law MCL 123.1102 only preempts FIREARMS. So to be safe avoid carrying a knife, as many cities have their own knife laws on the books.
I miss MI OCers and my family - but I sure don't miss some of those goofy laws back there.