I lugged it up the steps and went for a ride. Low gear won't climb the mountain but all the hills are no problem. With the extra weight of the add on it should be fine. It also rides more solidly with the front fork redone. The pedals might scrape when turning but there won't be any lean with the sidecar attached. The shifter needs to be relocated further back to stay out of the way when pedaling. It will definitely need another brake so I'll try the front disc mount again.
I'll take this damaged frame and cut off the dropouts and parts of the stays for the third wheel. I'll need the dropouts to mount upward from the base frame so the rider's base sits about 1 foot off the ground. The axle is 15" high on a 26 x 4 wheel.