TBH i would stay over, it took a fair few hrs to do a members car when we went for the RR meet there it was a 1.6 16V with a few mods the map was sent back a few times and was on the rollers alot to make sure it was right, which is what you want.
But if it is 6hr drive and maybe 6- 1/2hrs mapping it may be a long day might be worth staying over.