Per my insurance (State Farm), if I buy a vehicle, it is covered under my old vehicle's plan for the first week or so. That allows me to buy on a Saturday and inform the company of the purchase on the following Monday or Tuesday without penalty.
When I purchase my TT, I bought in Nevada where it is a "plate goes with person" system and brought it back to California where it is a "plate goes with vehicle" system. I had gone to my local DMV to see about a temporary transport permit. She gave me a permit to bring the TT from my house to the DMV. There was no permit to drive the TT from Nevada to my home in California. As long as I had my bill of sale and the DMV permit, I felt confident that I would have no problems as I'd be transporting it through only te two states for a period of less than 3 hours.
In the OP's situation, I would contact both the Ohio and the PA depatments and make sure I was in compliance with both states before transporting it - that way I could show compliance to any state during the course of my transport.
In California, I could not get the TT registered without bringing it to the DMV office for VIN verification - so there was no way to license it prior to transporting it into the state. I suspect the CHP knows that and won't ticket you for non-registration during your initial transport...
