I leave the switches on the TrippLite itself set to how Roadtrek set them when I took delivery of my 2011 190. I have not touched that switch in 7 years. The TrippLite should be set to Auto/Remote - this allows the wall switch inside the Roadtrek to take control of the TrippLite's functioning. When the Wall Switch is OFF - the TrippLite is put into CHARGE ONLY - which means your batteries will charge when the van is driving, you are plugged into shore power, or you are running the generator. ALSO - with the Wall Switch OFF - the inverter function is not going to send power into the few outlets that Roadtrek connects to the inverter in the TrippLite - which is a good thing because the inverter will drain your batteries quickly - even if the battery switch is off. When you need to have 110 volt power from those outlets - and you ARE NOT plugged in or running the generator - that is only when you put the Wall Switch ON - and then shut it off as soon as you don't need the outlets.
IF you put the slide switch on the TrippLite to the middle OFF position it completely shuts off the TrippLite. If you forget to put it back on before you leave for a trip, your batteries will not charge, and you will have no power if you plug in or run the generator. It is too easy to forget to put it back to Auto/Remote and this is why Roadtrek in later manuals perhaps than you have says to always leave it in Auto/Remote.
Also in your Roadtrek - contrary to other advice here before you plug in or run your generator always turn on your battery switch. Roadtrek put signs in my 2011 190 to ALWAYS turn on the battery switch before plugging in or running the generator. You do not need to turn on the battery switch if you are driving and the batteries will still charger through the TrippLite - but you can put it on if you want if you need 12 volts in some part of the RV part of the coach while driving.