re: Want to take a trip to Italy - Thoughts on length of stay, cost, and places?

I was stationed in Italy for two years. I would say stay for 10-14 days. I would try to stay in Florence. It's basically halfway between Venice and Rome, and it's less than an hour from Pisa.

Naples and Pompeii are a little further south, so you would want to stay overnight there. Naples isn't great, but it's near Pompeii and that place is amazing.

Toarmina is on Sicily and is beautiful! You can watch Mt Etna spew lava while eating dinner on a cliff overlooking the Mediterranean.

Start learning Italian; it's very worth it. And will help you when using the train system which is the best way to travel around. The express trains are more expensive (I liked the Eurostar) but it prevents potential run-ins with gypsies who are known for theft.

No matter which area you chose to explore you will have a wonderful time!