Ok, for car carry read this:
O.R.C. 2923.16 Improperly handling firearms in a motor vehicle.
(E) No person who has been issued a license or temporary emergency license to carry a concealed handgun under section 2923.125 or 2923.1213 of the Revised Code shall do any of the following:
(1) Knowingly transport or have a loaded handgun in a motor vehicle unless one of the following applies:
(a) The loaded handgun is in a holster on the person’s person.
(b) The loaded handgun is in a closed case, bag, box, or other container that is in plain sight and that has a lid, a cover, or a closing mechanism with a zipper, snap, or buckle, which lid, cover, or closing mechanism must be opened for a person to gain access to the handgun.
(c) The loaded handgun is securely encased by being stored in a closed glove compartment or vehicle console or in a case that is locked.
Must notify LEO if you are stopped for a law enforcement purpose.
Rest areas: You can go into the ones that are only a bathroom. If they have a welcome center or visitors center, its a gray area and I would avoid.
You cannot go into any place that serves liquor for on sight consumption. You can go to the Stop N' Rob that sells, because it is not sold for on sight consumption.
Signs hold legal weight. If you go into a posted facility, and you are carrying, if you know its posted when going in, your in violation and can be charged with criminal trespass. The owner does not need to say a word to you, just call the LEO's and its a bad day for you. The sign was your notice you could not be there.
No carry into government buildings. I dont know where the CMP is, if it is ON Camp Perry, I am not sure if you can carry there or not. Call and ask.
Check handgunlaw.us to see if I missed anything.