In reply to herbe_rouge:
Thanks Steve. In previous years I've been on parts of the EBC on the way to and from some of the trekking peaks and I agree it can be unpleasantly busy on the main EBC trek trail. Unfortunately tourist numbers were about 70% down for October in Nepal due to earthquake concerns, but obviously this is expected to return to normal levels by next year.
The Dolpo trek was fabulous and we didn't meet or hear of any other trekkers or other western parties over the whole 19 days. However the route we went had quite a number of >5000m passes to get over, including the Mu La at 5700m and some young children could struggle with this? There's no tea houses in the region so it was camping every night, some kids would love this of course!
I agree with Martin that Annapurna could be a good option for children. Maybe a bit busy in peak season, but no where near as busy as EC. Other possible areas to trek with kids could include Langtang and Rolwalling. Neither require flights and both are much much quieter than EBC. However both were badly affected by the earthquake (particularly Langtang) but here's hoping they are back to near normal in a few years time.