Lights, water pump, fridge, usually stereo, fuel station, antenna booster and heat are all 12v.
TV, water heater if elect option, microwave, AC are 110v shore power.
Fridge will run on LP but need power too, either manual or auto 12v or 110v.
Water Heater is gas with electric ignition, some have combo gas and 110v heat.
Most of the time the normal length of cord with the Hobbi will be fine, but having an extra heavy duty extension cord doesn't hurt.
I've always carried a normal 12-15' dump hose and another one to be safe, use it on occasion so I don't have to hug the dump hose depending on the site.
I carry a 12' and 50' water hose, the 12' works most of the time but that 50' is a life saver at some campgrounds.
Toy Haulers have a heavy tongue, you defiantly want a weight distribution hitch setup. I went with the Equalizer brand as it has sway control as well.