Hello Big Kahuna
The new bike, a Kona Big Kahuna, fit perfectly, and rode wonderfully. It’s a 29er hard-tail. I got the 18″ frame, which turns out to have an effective top-tube length of about one inch less than my old bike. This might still be a little bit big, but it’s pretty close. I took it out on my usual Willowdale ride today. The bike just seems much better balanced front-to-back. The top tube is shorter, but the chainstays are longer. This made climbs quite a bit easier, with less of the unicycle feel of the old bike, where I had to put my chin to the handlebars to keep balanced.

The 29er wheels are a huge improvement, with no real down-side that I could feel. They roll over things much better, and the bike feels much more stable at low speed, which makes the bike feel more nimble for tight spaces, rather than less, as you might expect given the larger wheels. Climbs were much easier, given the better balance and traction.
Brakes are the other major difference. They work, require light pull, and work the same every time. My old rim brakes seemed to be a bit random and spongy. Beyond that, everything about the bike is a step up in quality.
I’m hoping to get another month of riding in before winter. I dark cloud of sorts is that I have a nagging injury from a crash last week, perhaps a cracked rib, which may slow me down.