Or we can have you back in half a day (like the travel time for your shuttle flight). Or we can have you back in 5 minutes if the captain told me to step on it and don't spare the antimatter.
The bottom line is that in TMP there is no way to tell how fast the warp shuttle was going in order to derive a distance from Earth to Vulcan and there is no way to tell what speed Scotty meant when he asked Spock about going back to Vulcan after Kirk requested a proper shakedown cruise (which also means we can't derive a distance to Vulcan.)
As to XI - as Kingdaniel recapped, there isn't any way of telling how long the total trip was from Earth to Vulcan.
The bottom line is that in TMP there is no way to tell how fast the warp shuttle was going in order to derive a distance from Earth to Vulcan and there is no way to tell what speed Scotty meant when he asked Spock about going back to Vulcan after Kirk requested a proper shakedown cruise (which also means we can't derive a distance to Vulcan.)
As to XI - as Kingdaniel recapped, there isn't any way of telling how long the total trip was from Earth to Vulcan.