How many people? Ive been to brunch at Cafe Winberie in Ridgewood for an anniversary party--but it wasnt a private room. There is also the Glen Rock Inn, or The Porter House Steak House Sunday Brunch Buffet in Montvale. For Only ($19.95/Person) Incl. Unlimited Oj, Mimosas, Tea & Coffee, etc. There is also the Woodcliff Lake Hilton, but I think its pricey. Or the Sheraton in Mahwah.
Check out this link
The Porter House
125 N Kinderkamack Rd, Montvale, NJ 07645
The Steak House
455 Passaic St, Hackensack, NJ 07601
30 Oak St, Ridgewood, NJ 07450