I'll try to answer all your questions and will probably end this post with a few more of my own.
1. Yes, I have an eBikeKit emotor on my Villager. Based upon the website image and the fact that it can be programmed to max out at 28 mph (although mine is set at 20 mph), I believe it's the geared version. However, I've significantly exceeded 20 mph on a downhill stretch, of course.
2. E-assist is indeed ON most of the time. I have it set at Power Level 2 (out of 5), with 5 being the highest) because 1 is too slow for my taste and 3 and up is too fast.
3. While I could drop to Power level 1, that would require me to use the throttle frequently to support my own effort to ride at the speed I like (9-11mph). Power Level 2 keeps me in that range pretty consistently without using the throttle. With Power Level 2, I use the throttle only to quickly speed up in an emergency (like a dog chasing me, or quickly getting across a busy intersection) or occasionally to get going from a full stop on an uphill if I'm in the "wrong" gear..
4. While my 69 year old legs would call my riding area moderately hilly, a serious (and/or younger) cyclist most likely would not. We have rolling hills and mountains (the Adirondacks), but it's far from Tour de France levels.
To clarify - in order to ride at my preferred speed on my preferred Power Setting of 2, I find that I need to use the gears on the largest front sprocket (ie -52). My limited research (being a "newbie" at all of this) indicates that it's not good for the components to ride "Big" in front and "Big" in back. Hence my concern about riding on the "Biggest" (52) front sprocket most of the time even though that sprocket is compatible with the usual effort that my old legs can provide. Dropping to the 39 (middle) sprocket makes pedaling too easy.
My goal is to give my legs some exercise, and not "ghost pedal" much of the time, but I don't want to be totally exhausted at the end of the ride either. 52 seems to be my sweet spot to achieve that. So, I'm thinking that my best option is to have 52 as my MIDDLE sprocket.
Sorry for the wordiness, but I hope that I've captured describing my dilemma.
So, any thoughts, advice, suggestions and options to consider would be greatly appreciated.
And, finally, my questions: In order that I learn the "language' that you all speak (LOL) what does the "cassette" refer to as opposed to the "crankset"? (Note: I do know what a derailleur is....)
Thanks much!