For first time into TH, best to have original VOC. Depends on the TH Customs officer, sometimes they only want original, sometimes photocopy will do. But for first time, as car not registered in the system, best to have original.

You can't save Google Maps TH map into your phone, it's a copyright thing. So, I save HERE maps. But the accuracy of both maps can be horrible out of town. Even driving in town, it can be tricky as TH town roads are narrow & GPS inaccurate.

Remember to return the TH Customs form (for your car) after you chop your passport at departure. Failing to return will incur penalties ($$$$) the next time you drive in.