The sprint that they are close to is presumably an intermediate one so I'd expect only a handful of riders to contest it. Personally, I'd bring kids to a KOM point or just before it. Expect the actual finish to be crowded but it should be interesting if you get near to the run in.
More information here.
http://www.tourofbritain.co.uk/stage...p#.UjnETxVOPIU