Although we don't have the e-trek model, we have a similar set-up on our SS Agile; I agree with obragham above. Keep in mind that what I describe below is while NOT being plugged in to shore power -- happily, we find we very rarely need to do that.
What's important to realize, IMO, is how the "PowerSaver" switch operates: When it's in the ON position (PowerSaver ON), the inverter is supposed to sense any load on the 120VAC circuits; if it senses nothing, the inverter will remain off. If it does sense a load (something 120VAC has been turned on), it will automatically activate the inverter. This means that any 120VAC load will cause the inverter to turn on: AC, microwave, something plugged in to a 120VAC outlet and turned on, etc.
I keep my PowerSaver switch in the OFF position all the time (center position on 3-way rocker switch), as I don't want the inverter to turn on unless I want it to, as it will very quickly deplete the coach batteries if you're parked and the engine's not running (we also have the "underhood generator").
To that end, I do as was mentioned above: always leave the switch on the inverter turned OFF and use only the remote switch above the sliding door.
When I want to make my coffee in the morning, for example, I'll turn the inverter to full on -- PowersSaver switch in OFF position, which will tell the inverter to turn ON. I know, ridiculously counterintuitive! I make my coffee, then return the switch to its center position, meaning the inverter will turn off and stay off. To repeat: the only rocker switch position that will keep the inverter off is the center position.
My belief -- the PowerSaver switch might have looked good on paper, but it's a terrible idea in practicality.
As an aside -- once, while demonstrating the inverter to an interested visitor, I used the switch on the inverter to turn it on... and then closed the rear doors and forgot about it for 2 days while parked in my driveway! I'm pretty sure I substantially reduced the capacity of my four coach batteries by thoroughly draining them, but so far they still work adequately, for the most part. My bad; down the road, that's going to be an expensive mistake to rectify!