Hook up the sewer hose but don't open the valves. Normally you don't even want to dump the "black" tank until it's at least half full, and 3/4 full is better. However if you're just going to return home and let the Motorhome sit for awhile you'll be dumping the black tank regardless. I would still suggest you try and fill it to at least half by adding water by flushing a toilet or some other means.
Then the order of dumping is usually; open the black tank valve first and empty that tank. Close that valve and open the grey water valve. That way the grey water flushes out your sewer hose. You can clean the hose further after disconnecting it from the Motorhome by leaving it connected to the sewer and running fresh water from the hose bib through it.
Lots of liquid in the black tank as you use it will help prevent a buildup in the tank. Start with a few gallons of water in an empty black tank. Then be generous with the water whenever you deposit solid waste into it. It's better to add too much water to your black tank than needed so you have to dump it more often, then not having enough and ending up with a buildup problem that requires a professional to clean out the tank.
Just as an aside, we store ours in a large waterproof bag in a storage compartment. It's usually not completely dry when you put the hose and fittings away so that way any liquid goes in the bag, not onto the floor of the bay.
Have fun on your trip.
