I think Mary's advice is about the same as mine. I'm now 57 and I sail my Hobie 18 Magnum alone much of the time. You can work it fine as long as you're safety-concious about the righting thing; I use a righting pole and can get it up by myself. You should be able to handle the main sheet with one-hand though. If the stock 6:1 doesn't work, try making it a 7 or 8:1.

Wyatt