I am a newbie here with limited experience ... however ... if hills are involved, you want mid drive. I think the gears in the back and mid drive will work.
Yeah, mid drive makes all the bike salesmen & chain salesmen & pro chain replacemen happy. Hill does not equal mid drive. Hill greater than 1000' rise in an hour equals mid-drive. Rockies, Sierras, Alps only. I cross 80 hills weekly with a front hub motor, 3 of them 15% grade and some others close to that. 200' total rise.
It is nearly impossible to buy a geared hub motor >500 watts these days. US vendors won't sell 48 v geared hub motors either. See above. People buy them then the first weekend then immediately try to go from Huntington Beach to Lake Arrowhead in one run. Burnt motor, warranty claim. I had a 1000 W Mac12t, loved it, rain burnt the pins off the ASI controller into the harness. Can't buy another one, except maybe in pallets of 8 from factory in Shanghai on alibaba.
Easiest front geared hub conversion is ebikeling.com . everything matches. Stupid lying displays and too fast too quick PAS1 on the one I bought in 2017, but everything matched. Worked 1st time. Still using the controller etc. That motor wore out the gears in 4500 miles.
OTOH if you want to save money and buy the controller, pas pickup, throttle, brake handles one at a time off ebay, batteryclearancewarehouse.com has bafang 500 w front hub motors for 36v for sale now, $23 each. No wheel. I have had trouble buying anything that matched on ebay. Even if the connectors are labeled on the ad, when the controller comes in the labels are all in Chinese.
Alternative is "1000 w" or "2000 w" direct drive hub motors. Total misapplication climbing hills with these. They won't burn up, but they will eat vast quantities of watthours going slowly uphill.
Don't use a front hub motor on slick or muddy rocks, steel plates, wood bridge decks, or on ice. Pedal or push when that occurs.
OTOH, when I loaded a MTB like that I got 23 lb front wheel 118 lb rear wheel without me on it. Weight on the back lifts the front wheel. I pitched over the handlebars on my chin 3 times, and once was knocked over by a dog charging the front wheel. Front wheel would hit a bump, stick, rock, snap sideways and up the seat would go. I haven't fallen off the stretch frame cargo bike yet. You can get used ones, unpowered. Stretch frame cargo bike puts rider weight on the front wheel, cargo on the back. Xtracycle yuba blix packa mongoose envoy are names to cruise craigslist ads with. New Mongoose envoy was about $750 new when the conversion was done listed on this topic. Avoid the old shimano 6 speed rear axles, they are too thin & one broke under my enormous 180 lb. No cargo that day. I converted my yuba bodaboda for about $840, 630 of that the battery. ebikeling batteries are cheaper than that. But I have 840 wh.
