We plan to rent a car at the Milan Linate airport and drive to Bellagio for the weekend. Anyone been that route and any suggestions?

You might want to pickup a map before you go. I have som e map info on the web site:
Italy: Driving - Road maps

Or pickup at least a Michelin map at any good bookstore.

There are many route planning sites - but I have never found one where I can actually navigate using the directions. Instead I use my TCI map. But, here is one:
www.maporama.com

I have more of these sites list here:
Links

Been that route and found it fairly straightforward. Meaning, we never got lost, but there were hairpin turns!

It is beautiful up there.

I've driven it in the opposite direction and other than the before-mentioned hairpin turns near the lake, all was easy and straight forward.

When are you going? The wisteria across from the Hotel Florence blooms in May. Beautiful.