How much time do we spend in the lake region of Italy

Is it enough time? That depends on your interests. It would be enough time for me! What are your plans for those 5 nights between there and Assisi? If you are looking for recommendations, Verona would be ideal for a couple of those nights with a day trip to lake Garda thrown in. Or Venice, Ravenna, Florence...

Those 2 nights before Rome, why not add those to Rome? You could spend a week in that town and only scratch the surface of things to do there.

Hi, can you give us a few more details, so we share our recommendations based on your ideals?

Is this your first time to Italy? If not, where have you been previously?
What would make these 11 days perfect for you, i.e. scenery, activity-level, etc.? If it was raining in the area, what might your Plan B look like?

I think of the lakes as primarily relaxing destinations. Even if you're planning sidetrips, three nights at each location should be enough. For balance, I would want the next stops to be more different, not more lakes. Are you avoiding or have you already been to Venice and Florence? What about Verona and Padova, or the Cinque Terre and Lucca?

I agree with Laura. The point of the lakes is, as Rick says, that there are almost no "turnstile" attractions, and to "see how low you can get your pulse." If you want something more than that, be sure to vary time at the lakes with time in other places.

And I agree with having a rainy day plan. The lack of turnstile attractions means there's very little to do when it rains there. You could take a daytrip into Milan or another city.