Hi Kevtrane,
I am on the MWL journey myself - so I can't say this answer is from a "veteren"; however, I hope it will be helpful.
Certain barbecue sauces and salad dressings are "MWL legal". Do you have Dr. McDougall's book on the program? If so, you can refer to the list of specific brands given there. This website also has a list of allowable foods that include salad dressings and sauces:
http://drmcdougall.com/packaged.html (The link is in the very uppermost top right corner of the homepage, on a tab labeled "packaged foods").
There are certain general criterion that you should look for on the labels of the products to assure their suitability for the program:
Salad Dressings:
Must contain
no dairy products (including whey, buttermilk etc.),
no fats, and no oils. Should also be low sodium.
Barabecue Sauces:
These should contain
no added fats or oils. Since most have added salt and sugar, and some have preservatives, commercially prepared barbecues must usually be used sparingly!
If you are unable to find McDougall-friendly dressing and/or barbecue sauce when you are away from home, perhaps you can carry some with you. You can also experiment with other toppings that will be tasty, while still being "legal", such as fresh salsa, fat free hummus, vegetable/bean soups etc.
Mary McDougall has recipes for McDougall-friendly sauces and dressings in some of her recipe collections.