That depends on a couple of different things. First, of course, is what kind of shape are you in? How much can you lift by yourself, how flexible are your joints, how is your balance and coordination and how long can you work without a break?

Second, what kind of building space do you have? Is there room to lay out materials and tools without having to constantly be moving things around? Can you rig block and tackles and clamps and braces and stuff to do things that you can't?

If you haven't already done so, you can check out the construction gallery for the boat to see what's involved. The guy building that boat has a gray beard and seems to be managing fine. I'd say that solo construction in general is easily in the range of anyone who regularly sails dinghies and can lift 50 lbs or more right until it's time to flip over the boat or move it to the trailer. That's when being able to rig a block and tackle become important. Or, you could use pizza and beer or just hire a couple of youngsters for half an hour.

Laszlo

   I promised boat rides to neighboring kids to help get my Rhode Runner flipped and moved a few times.  Actually have had to make good on the offer more than once - to the point that I went out and got a good tube to tow them on, which gives a good excuse to go out and have some fun!