Lake Como (Varenna) or Cinque Terre?

Varenna.

The Cinque Terre villages are not accessible by car and using a wheel chair would be a challenge since some streets are actually small steep alleys with stairs.

melinda,

Don't split your time between places! It will take about half a day to travel from one to the other, which means you won't have a lot of time to spend in either one.

A few thoughts on the two choices....

• Varenna - while the main part of town by the Piazza and Church is fairly level, as I recall you'll need to navigate some stairs to get down to the promenade that runs along the lake to the ferry dock (although you could go around on the streets, but that will be a longer journey). There's not a lot to do there for children, so taking day trips to Bellagio or other parts of the lake means that you'll have to access the Ferry dock. Visiting the ornate gardens at Villa Cipressi or wherever will probably also involve stairs.
• Cinque Terre - there are also not many activities for children there either. Exploring the five towns is a popular activity with many travellers, and that's easy to do via the local trains but stairs will be involved in getting from the rail platforms down to street level. You could also travel on the local boats, although that will involve walking up a narrow ramp. Sitting on the beach is also a popular activity, and of course just enjoying the ambience and the many excellent restaurants. Although parking is difficult in the Cinque Terre, Monterosso has pay car parks in both the "new town" and the "old town", and I've never seen them full. For two days the cost likely wouldn't be too extreme. Some hotels also provide limited parking for guests. Monterosso would be the best choice of the five, as it's mostly level and it's an easy walk from one part of town to another. However, for travel in July, it could be difficult finding accommodations at this late date, but you could try.

For driving in Italy, note that each driver will require the compulsory International Driver's Permit, which is used in conjunction with your home D.L. These are easily obtained at any AAA office for a small fee, and valid for one year. You'll also have to be vigilant to avoid the ZTL (limited traffic) areas, as hefty fines will result for each pass through one.

Stairs are pretty easy to work around in Varenna. If you walk along the main road, be aware that parts of it don't have a sidewalk. The lakefront passarella is pretty flatly paved with maybe just a few stairs; not terribly wide, about two people across. Boat rides and the road on the opposite side of the lake should also be manageable.

In comparison, tourist boats in the Cinque Terre are smaller, less frequent, more crowded, and are boarded by a smaller, not very stable gangplank. Taking trains between the Cinque Terre towns means a flight of stairs at most stations to get to and from the correct track.

First, good for you for not playing it safe or staying home, Melinda. The kids are going to love being there. So, I'd echo other comments and just add this: Varenna is a terrific combination of serenity and Lake Como authenticity. The kids tends to have fun traveling between the lake towns on the little ferry, and it's about as picturesque as it gets. Cinque Terre, by contrast, will be as tourist-crowded as it gets in July. Have a blast!

Great, thanks everyone for the advice. I think Varenna it is.

Good choice, Melinda!