Tonight I filled the bike with fluids, gapped and installed plugs, checked the valve clearance and checked things over. I think that the last thing is the exhaust (that doesn't fit, but that's another story), fill the tank and kick it over. We'll see how well that goes, maybe tomorrow.
On the sidecar front, I pulled it into the garage and had a closer look. I tried to pull some of the nuts and bolts apart but they are pretty well gone. I think that I'll try using electrolysis to remove/undo the rust and see if that helps. In the mean time, have a look at the awesome plate that is mounted on the nose of the sidecar: