If the wedding is on a popular weekend it can be pricey
this sub is not going to do any better than searching Expedia, TripAdvisor or Google for room rates for specific dates, and a wedding block might just give you the best rate available

Consider that locations that aren't the venue mean that they need time or transportation to get there

Look at the trade off of navigating the subway, walking, or calling Lyft, or renting a car & parking just for a cheaper room rate