Dumping at your site is probably the worst. No one wants to set up in a muddy spot. Dumping at the dump site is out since it takes way too long. Dumping while driving home has a downside too. I have been told by more than one experienced RVer that this is actually against the law and you could get a ticket. It seems that the state I live in doesn't want any RV dumping anything while moving down the road. Why they can't tell that the fw tank holds just water is beyond me.
I try to break camp with just a small amount of water left. If I have a lot I usually run extra water into my gray tank while cleaning out the sinks. The best place to dump the fw tank IMO is in front of your house on the street. The gutter handles it quite easily.