Regardless of what you do in the city, getting into the city with your rig will be the biggest issue. From RV Trip Wizard
LP-GAS PROHIBITED:
New York/East River:
Between Manhattan and Brooklyn:
Brooklyn Battery Tunnel. Between Manhattan and Queens:
Queens Midtown Tunnel.
New York and New Jersey/Hudson River:
Between Manhattan and Jersey City: Holland Tunnel.
Between Manhattan and Fort Lee: Lower level George Washington Bridge (I-95 South) and George Washington Bridge Expressway. Lower level Verrazano Narrows Bridge.
Between Manhattan and Weehawken: Lincoln Tunnel.
Doesn't leave a lot of ways to get into Manhattan.