Don't eat that differently in the van to when we are at home. Probably eat more meat when we are away and have a few more BBQs and fires
As others, we like to "shop local" when travelling, so have a cupboard full of basics and pick up fresh stuff along the way.
Best thing we've found for cooking is a small pressure cooker. Saves a huge amount of cooking fuel and water.
And as for cooking baked beans...oh yes...from scratch, over a wood fire...best baked beans ever!
(I tend to use this simple recipe:
http://www.deliciousmagazine.co.uk/recipes/baked-beans/)