Not sure it'd be practical where I'm at with the towns being miles apart, but a great idea in more dense areas. How do you deal with transporting things like a trip to the grocery store?
Now that's some crazy getup, i suppose the range and speed is going to be influenced by the weight and battery capacity, could be an interesting bit of research. For me it'd maybe a max of 400lbs for the two of us (I'm 6'3" and in the 230 some range alone) plus a minion and cargo. Probabbly 500 actually just to give some overhead, never good to spec things just at capacity.
Yes, it alsodepends on how much help you get from the motor. I can get between 35 and 80km out of my Ebike depending on the helping function I choose, how much headwind, how many hills, how much I'm carrying, etc. I went with a midrange battery for mine, but after experiencing the longer range use cases (going on biking holidays carrying my child or on day trips somewhere relatively far), I'd definitely choose the largest battery next time. I definitely think it's worth the extra 200-300 dollars.
I'll also do a shout out to Thule bike trailers. You can attach them behind any bike instead of having to buy a special one with front carrying, and they're super light, all terrain and can be easily removed when you don't need them.
Google pannier bags. They're basically totes that mount onto a bike rack. Some of them even have straps to convert them into a backpack for easy carrying.
In terms of distance, I think you might be surprised by how far and fast you can go with an ebike. A lot of people only think about their speed when on the highway, but most of your time on the road is likely spent at slower speeds navigating traffic in town. So what bikes may lack in speed, they make up for in maneuverability.
Sounds like a lot of people here have some experience with this. Where I'm at it's all towns of less than 2000 usually spaced 5-10 miles apart over a state highway. I could bike on it, at least in the summer. Might be worth a look, or just getting a decent analog bike since it can't really be my daily transport moving a kid and all. Been meaning to get one of those anyhow, last one I had was a shoddy thing not up to hauling someone my size.
One option to look into, especially for transporting small children, is a "bakfiets". It's a type of cargo bike with a large bucket in the front that can be used to haul kids and groceries. And you can find them now as ebikes to make it easier to haul more stuff. They're super common in the Netherlands for their high carrying capacity. You'll even see people moving furniture around with them!
My wife orders the weekly groceries home every 1-2 weeks. The delivery fee for purchases over 150.- is only 4.95, which easily pays for itself with the drive and the parking fee to the nearest shopping center (8km). In addition, in this setup i also have to carry the purchases only from the front door to the basement.
Edit: We use Public transportation a lot. For the normal bike we use the Thule Chariot Sport as a trailer. For the daily needs (fresh bread, somtimes mising butter or milk...) we shop localy in th village, also with bike and backbag or the biketrailer.
A decent cost, I'd guess the delivery is a store employee using a company vehicle since that'd be a heavy lift for $5 to take on in some 3rd party service or the employee's car like most small shops. Persoannly I like going to the shop, even if it's a little ways out just for the getting an idea on the fly aspect when walking by something.
Not the OP but I use a bag from Rhinowalk (I got mine from amazon for 85 Canadian dollars) that transforms from a pannier to a backpack and I love it! It's not the best backpack in the sense that only the top opens so it's harder to organize but I love it overall.