Which would be the best way to travel from Venice to the Lake Como area without having to rent a car?
You can go by train to either Varenna or Como (the town) in about 4 hours, more or less. From Venice you take the fast "FRECCIABIANCA" train to Milan; change there for the 1-hour ride to Varenna, or a slightly shorter ride to Como San Giovanni (which is set back a bit from the lake). Personally I'd go to Varenna---we loved it there. You can ride boats to other towns on the lake if you like.
And if you need a hotel in Varenna, I'll recommend Albergo Milano...4.5 stars on tripadvisor...nice rooms with balconies overlooking lake...very modern bathrooms...great patio for breakfast overlooking lake...you can't go wrong. We loved it. http://www.varenna.net/
Thanks both for the train a hotel tips!