My sister is a type 2 diabetic who travels a lot. What are some good things to keep in her purse to snack on?

Snacks for diabetes. Nuts and seeds--the best being walnuts and almonds. Low fat cheese. Peanut butter. Any protein/fat combination has a low glycemic index, thus raising the blood sugar slowly and will chase away hungar. Just be careful to not eat much because these are high in calories!
Glucose tablets. If she is on a glucose lowering agent such as sulphonylurea or insulin, she must have free access to simple sugar in case she experiences a hypoglycemic episode ( such as glucose tablets , hard candy). Granula bars and carb free snacks will also help her maintain bs during active time. If she is Insulin dependent, she is advised to wear a medical alert bracelet.