I just checked the CLC page for the boat. They estimate 120 hours; their estimates are a decent rule of thumb, but I've found them optimistic, especially for a first boat, and the fact that finishing (everything after that last coat of epoxy) takes longer than you might think. Off the cuff, because you say you have other experience, I'd guess 180 hours might be a rough estimate to be ready for the water.
It is very easy to fool yourself into thinking "I'm half done!" just about the time you finish all the filets and you've got a nice solid looking boat in the garage. Nope - the glassing and finishing will prove you wrong. With that said, I get very obsessed while building - the "trick" is to always do a few hours almost every day, and then add in some 10-hour marathons. Also to plan ahead and always have a few similar/smaller parts that you can do while waiting for bigger jobs to cure/dry or whatever. Even with a full time job my NE Dory took about 3 months, each of 2 kayaks about a month, and my Rhode Runner 4 months. Only on the Rhode Runner did I keep a build log: 408 hours of work - that is fully finished with all hardware and motor and electrical installed, trailer bunkers adjusted, etc. ready for launch. This was my 4th build; I was certainly more efficient than my first.
I just looked at the CLC estimate and they say 250-300 hours to build the Chester, so again, that's not a bad estimate for an experienced builder.
Some specific notes:
With you being retired, you have the luxury of time - longer work sessions result in less wasted time (less percentage of time prepping, cleaning up, turning lights on, finding tools, etc.).
If you have only a two-bay garage, you can certainly get the job done with only using one bay, but much nicer and easier to use that second bay and have a couple full size work tables set up near your build (you can get the plastic folding tables at a box store for $40 or so, and they work fine) plus a more solid work bench if you can fit it, too. One table for all your epoxy, tools & etc.. Another for all your semi-completed parts, putting freshly clamped parts aside to set up, etc.. And the work bench for "working."
If your garage naturally stays at 44F, I'm guessing that with just a little added heat you'll be able to work all winter. You will want several electric heaters to bring temps up to about 55 while you're working, 60 is even nicer on the fingers (and epoxy). I would wait for warmer weather if you can't get up to at least 50F while you're working. You get to decide if you want to let the temperature drop back down (and how far) when you're not working, but cure time (and paint/varish dry time) gets pretty long at temps below 50.
-Bubblehead