Hey, thanks Mr Kirkland, great tips
Hi Tonyd, we're also travelling with kids (a bit older, 9 & 12). We'll be doing a fair bit of wandering around and sampling the cheapo delicious food. Here are some of the other places we have bookmarked...
Museum of Emerging Science and Innovation - there are robots!
Exhibition, 5 contemporary picture book illustrators - Flew Gallery, Sendagi (near Yanaka). http://www.tokyoartbeat.com/event/2017/6115
Edo - Tokyo Museum (primary school kids free), adults 600Y
V useful is okyo Cheapo's info on playgrounds in Tokyo, and here's another collection http://bestlivingjapan.com/top-10-recommended-baby-and-kids-parks-in-tokyo/
As recommended by TC, we will also head to Inokashira Park on a Saturday to check out the street musicians. We have also booked (waaaaay in advance) for the Ghibli Museum as we're all fans.