April or October for Lucca, etc

I agree with Ken regarding April vs Oct, although both time frames offer lighter crowds. Go late March or very early April, if possible.

nancy, Based on my experience, either April or October should be good in terms of "least tourists", however it's just about impossible to make any recommendations on "best weather". Weather Underground or other sites will provide predictions based on past history, but this could be entirely different during your trip. I've been in the C.T. and northern Italy in late September / early October and the weather has been great (albeit a bit cool in the evenings). I was in Tuscany in mid-May last year and the weather was uncharacteristically cool and wet. Of the two dates, I'd be more inclined towards late April, but you'll have to "take your chances" either way. Good luck and happy travels!

In my experience, you will get rainy days in October. Didn't bother us -- you just have to be prepared with coats etc. The big advantage is far, far fewer people around. Much more enjoyable.

April. It stays light out later.

Regardless of the weather, April and October are different food seasons, which I suspect is important to most Tuscan travelers. In the fall: grape harvest, olive harvest, wild game season, porcini mushroom season, chestnut season, truffle season.... I have not been in the fall, but I'd sure like to do so!

In April, the flowers will be blooming, FWIW.

I was in Lucca, Siena, in April the last two years. Perfect weather and it is light later.

We visited in October and it was beautiful. I think April would be very nice also. You can use this to check potential weather for the two: http://www.knowital.com/weather/lucca/