Don't wanna scare you Jay, but I had the same issue- turned out the frame was bent....
but not to say yours is.....!
Possible that (and looks like it is-easy fix?) the wheel is offset to cater for the tyre/chain clearance (how wide is tyre?)
Do you have the proper wheel components, this is important, not for originality, but for ease of function....as I discovered...!
There was chat about this not long ago, no time for detail now, but I set mine up with string lines kind of like setting out a construction.
Before you go berserk though, I reckon best to have at least the gearbox in place so you can check sprocket/chain alignment first.
Have to leave it there, that should be enough to keep you busy.....