So apparently the route I took round Central Park is 9.7km, which explains a lot. This morning I checked out Morningside Park, but it's really too small for running - there's a loop of about 400m at one end, and you can go down the long bit to 123rd St, but it gets boring very quickly. Most of the park is taken up with a big hill and stairs. I'll try Riverside Park on Thursday, or find a shorter loop at this end of Central Park.
This morning I had breakfast at Nussbaum & Wu, because it seemed like a good name. Then I went to Duane Reade down the road (a pharmacy open 24 hours a day, which is quite impressive), and picked up some hand soap for a couple of dollars - none is provided in the bathrooms (and I didn't read the checklist about what to bring). And if anyone forgets/loses their wherever-to-US power socket adaptor, the Best Buy in Union Square has four left.
So far I've missed about three sponsored meals. In related news, if you ask for all the salad at Subway in the US, you seem to end up with something much hotter than in the UK.