Since you are on a tight schedule I think your plans are fine. Most would say 3 or 4 days in both places, but I would only suggest to leave Montreal early so you can get the most out of QC. The drive is about 2 and a half hours, very easy. Depending on where you stay, you can explaore both Upper and Lower towns, but again taking the time to greatly explore the museums, or some historical sites could be limited. Stay in Old Quebec if possible so you can maximize your experience there. Evertything is within walking distance there.

That sounds about right. The two cities are actually quite different, with Montreal being big and cosmopolitan, and Québec, at least the old town, a sleepy but tourist-filled French village. If you have time, you should try to make it to the Montmorency Falls, too -- very pretty, and it's only a short drive...

If you have time for one single museum in QCity, make it the Musée de la Civilisation (http://www.mcq.org/index_en.html), in Lower Town - immensely popular among kids, with several interactive activities. There is going to be a festival in the Chutes Montmorency area while you're here. See …sympatico.msn.ca/MonQuebec2008/…

I do not know hjow old are your kids, but there will be family oriented activities at 'Espace 400e' throughout August: …sympatico.msn.ca/MonQuebec2008/… There is a special exhibition held at Château Ramezay for the 400th anniversary of Québec City, your kids might enjoy: chateauramezay.qc.ca/eng/expo/peursbleues.htm

Toooo bad you will miss the Celtic Festival, launched on Friday August 29 ...