Drilling the cam sprocket bolts out turned out to be fairly easy. Used letter drills and then a step drill since I don't seem to have a drill big enough. Went up through each letter drill from A to Z to minimize how much hard material each bit had to cut through.

With the cam sprockets removed, I went ahead and took off the right hand cylinder head. That's where the cylinder that lost compression is. Surprisingly, the cylinder walls are in good shape with cross hatching still visible and no significant lip. It was clearly burning oil in both cylinders on that side. I'll need to tear down the crankcase to see the piston ring lands.