I pulled out my tools, and tracked down the power drill
I didn't have my power saw, so I it was a lot of hand cuts with my crosscut saw. Fortunately the wood was pine, so wasn't like trying to saw through hardwood.
It was a lot of cutting, let me tell you.
I didn't want to risk splitting the wood, so I took the time to pre-drill all my screw-holes.
Part of the problem we were having was that the pre-fab railing at Lowes were not long enough to reach between the columns we were building this around. In order to remedy this, I built boxes to fill in the gaps. The top here is just over a foot across.