Italian Lakes - which tunnel??

Thinking of doing some of the Italian lakes next May, then onto Austria and Germany.

We are quite happy at travelling through France to either of the tunnels, Mont Blanc or Freus but would welcome some advise from those who have travelled that way with a caravan.

Where would you look at spending the night before crossing over and which tunnel and why.

Once through the tunnel's is it easy to reach Maggiore the same day, would like a few days there so where is a good site for cycle trips out, looks like there is lots of sites to choose from but its a big lake where is a good place to site ourselves.

We don't intend on doing all the lakes just a couple, DK on another thread suggested Lake d'Iseo as a nice quieter one, I've found a site that I think will suit. 

Many thanks in advance for any helpful interesting suggestions.