I'm on the metaslim blue menu right now and my family and are doing a cub scout outing tomorrow. I didn't realize until this evening that it's a whole family event.

Breakfast will be at home so no problem there and we will be on a bus for a couple hours and have a sack lunch. I'm planning on packing a salad topped with tuna, (using my kids' frozen juice boxes to keep everything cold)and my HNS for lunch.

I can throw some HNS's in my purse for snack. I'm worried about water and supper. 2 hours each way by church bus means limited bathroom access and supper has me completely stumped. The group is planning to do a fast food stop for supper.

What would you more experienced MRCers do to stay as much OP as possible on a group outing involving fast food? I can take my own food to a point but I won't be able to keep things cold or have any way to cook for the supper meal.

There is almost always a grilled chicken salad at a fast food place. Generally, the chicken has added sodium, so you don't want to do it all the time. For example, the McD's southwest grilled salad without tortilla chips has veggies, chicken and black beans/corn (which would cover your starch). At other places, if you packed melba toast or low carb tortilla to go with your salad, you'll be good to go.

If there is no salad, I would order a grilled chicken sandwich with no bread. Is it the most attractive dinner out there? No - but it's life and you won't have to pay the carb monster the next day. Drink plenty of water to flush the sodium. Many places have water fountains where you can refill your bottle - or maybe take a gallon jug.
Good luck!