I didn't read all the comments but would like to say that we went to NY for siteseeing the last two Augusts.
We used priceline for the hotel (but you already have a free place to stay - bonus!)
Definitely get the 48-hr Greyline tour ... three tours that will give you a great overview of the city! We got the vouchers on-line prior to visit. Discount with
AAA membership.
Statue of Liberty Crown / Ellis Island ... again, purchased these on-line. If you are physically able, it is awsome to go up in the crown ... but don't expect to get tickets if you don't book on-line a few months out. For Ellis Island, plan to spend at least 1/2 day and get the audio tour for that.
Get discount certificates from Restaurant.com.
Familiarize yourself with the subway system ... easy to get around. You can purchase multi-day passes which I recommend.
I work for a large company who donate money to many of the NY museums ... I was able to get free admittance into some of the museums. You may want to check with your employer to see if they have any discount programs for NY sites.
We loved Radio City Music Hall.
A couple of the restaurants we went to that we loved were:
Pongsri Thai on 48th St (reasonable and good)
Tony's DiNapoli on 43rd St (Time's Square) ... a wonderful family-style Italian restaurant ... exactly what you would imagine ... lot's of fun
Blaggards Irish Pub on 38th St
We went to Tony's both years ... not cheap, but not too expensive either. Last year we sat at a table right next to a Golf Channel anchor ... I didn't recognize her, but my DH did and he got a photo with her.
You will have a great time with a little planning and education beforehand.
============
We were four adults w/ RT from Detroit, four nights in NYC - here's a breakdown of our expenses for the trip:
Transportation (including RT air, airport parking, taxi to/from LGA, METRO card) = $588 (Spirit Airlines)
Hotel (W on Lexington - 4 star thru Priceline) = $629
Tours (Statue of Liberty Crown, Greyline, Museums, Radio City, NBC, Empire St) = $526
Food (4 sit down restaurants w/ drinks + cart lunches ... brought own breakfast) = $646
Souveniers = $101
So we did all this for 4 adults for about $2,500.