Other than the diversion at the end from Milano to Como back to Milan, I don't think that's too ridiculous. The stop for a day in Genova is basically on the way to where you want to go in France, and while you could extend that to a couple of days, I think you'll be fine.

Regarding weather, I'm not the best person to give you an opinion. You live near Cancun and I live in Portland, Maine. That said, early fall is probably a little bit warmer there near Milano and Como than it is here, but probably pretty similar to most of New England if you've ever been up here for what I'd argue is our best season. Personally, I think you're in for some great fall weather, provided that you're comfortable in the 50's (F).

Some may suggest Portofino instead of Genova, but my mother is from Genova so I'm not allowed to tell you that. As a chef, you're in for some really great Ligurian seafood either way.