Every selling state is different, every buying state is different.
I recently purchased a truck in Washington State where the sellers keep the plates (it was a dealer so no holding on to the plates) and I was going to California where you have to have an application in process, fees paid and smog check done to even get a temp. The dealer put a 3 day temp on the truck and gave me a blank to fill out as I wanted (I didn't use it). Needless to say after 3 days I was still in Oregon and wasn't able to get the registration completed in the three days. I just pulled the temp and ran with no plates, it still took me about 6 weeks to get a temp from California and another couple to get the plates.
Alan