Personally I'm not a huge fan of crafting at that age. I usually feel like I wind up doing most of the crafting, and the child winds up roaming around the house getting sticky gluey fingers all over things

.
I much prefer activities like painting/finger painting, coloring, etc. Things where I am obviously still supervising and interacting, but the child is a lot more self sufficient in the actual DOING.
As for play dates, I'm generally pretty willing. At this age make sure they're not drop-off (otherwise your nanny is just babysitting an extra child for free). It can also be awkward for a nanny to have a playdate with MB's friend. You might ask if she has any nanny friends with similar age charges, or else try joining a play group or class where they can work on those same skills.