As an old New Yorker and a 6 month a year resident of Florida, I must mention the weather in August.
NY- varies from quite nice summery temps to IMPOSSIBLE.
DC-Can be quite warm/hot. (Check to see if the National Gallery has a hanging photo show. They usually do a great job.)
Fl-IMPOSSIBLE/Both very HOT and HUMID 24/7
If Orlando and the theme parks are on your itinerary, just be aware that it's inland
so really HOT & HUMID.
Just advising so you know what to expect and packing can be done accordingly. Hey, the wife and I were in London one year when it hit 103F. 'Twas the hottest in over a century.
Been in Mittel Europa in June and you probably know what that's like. Just sayin'...
The pro shops mentioned above have everything; I've been a customer of two of them for years. 35mm color print film can be picked up virtually anywhere you find a tourist.
You're visiting in HIGH tourist season for NYC and any and all accommodations will be pricey and more-so. In Fl in August they'll pay you to stay with them (hyperbole), but rates for most places are reasonable.
I was a volunteer in the past at ICP and in the bookstore there was/is a monthly publication which details all current photo shows in the US. Pick it up.
First saw the light of day in NYC not quite 80 years ago (will be 80 in 3 weeks), and without being snotty, believe me, and I've been fortunate enough to visit many major cities both in this country and Europe and adore any number of them, but...
Hey, as Ed knows, I do lots of street shooting in my town. Maybe we'll bump into each other.
Enjoy!!!