What type of vegetarian is your friend? Ovo-lacto? Strict vegan?
There are many great energy bar recipes that you can make at home with some nut alternatives. Roasted chickpeas or soy "nuts" can be used in trail mix to give crunch. I have a recipe for a quinoa energy bar that is nut free. Hummus and pita make great lunch fare that doesn't require cooking. Alegria is a nut-free trail snack that has both protein and calories (there is a recipe posted here for that). Muesli is great for breakfast with powdered soy milk and freeze-dried/dehydrated berries. Use shredded coconut or coconut powder to boost the calories where you would have normally done so with nuts.
My second book was vegetarian/vegan and deals with food allergies such as Celiac… so if you need any advice… I'm at your disposal. If you like, I can post a few recipes or you can send me a pm for them.