Stop in for a cup of coffee

Evening guys. Quick question, since the car is technically sold and the money is in my bank. Can I mail out the title and BOS to the person who bought my car or should I wait until its on the trailer and heading down the road? Would there be any reason I would need to hold onto the title while Im in possession of it awaiting the pick up? Part of me says mail the paperwork after its picked up, but Im just not sure..