Hi and sorry that you have had problems with the mounting of your motor. It's totally true the choice of bike has a lot to do with how easy it is to get going. An awful lot of bikes just are not good for conversion, even with a lot of work.
Post photos, a good deal can be figured out from looking at the problem. Chain coming off could be as simple as turning the sprocket over, the off set teeth should be on the spoke side for most installations. Without a photo hard to figure out.
There's a lot of help here. We can get this figured out
edit: plus I see your in PA. There are many here from Penn, depending on where you are chances are there's someone close to you that might be able to help you out. Even here in Boise, Idaho I've had people over here several times working on their bikes getting them going.
It's a community thing