H4G, I would suggest you post this question at the NS board, the people who are and have been successful with NS have really a lot of very good recommendations on working the program.
I personally visited my GF a few weeks ago and had to really dig my heals in and tell her this is what I was doing and that just had to be how it was going to be. She figured I should take a holiday from my program and I had to explain to her that my visiting her wasn't about the food but about the visit. She should go ahead and prepare meals for her and her family and I would match mine with her, so she fixed taco salad and I used the salad base and made a NS version using the taco fixings. She went to In&Out Burger and I had her bring it back to the house to eat and I fixed an NS Burger, she fixed scrambled eggs for breakfast and I used egg beaters and made myself a separate dish of scrambled eggs (I don't care to much for the powdered eggs so I didn't go their).
You can still have plans with your friends but the plans aren't about food they are about enjoying your time with your friends. The food, well you have to eat so it might just as well be your NS food. Keep some meal replacement bars in your purse and if you get backed into a corner order a salad, enjoy it with your friends and have your bar a dessert to insure you get the proper nutrition.