My picky eater wouldn't like rice, veg and cheese sauce (shame, as it sounds nice in a camping-food way!). She's a massive challenge. She did like: cheese Pasta'n'sauce with added tuna and sweetcorn; M&S tinned stewed steak with mash and peas. Not keen on corned beef hash made with tinned potatoes, but I think that's cos I couldn't get the potatoes to crisp up on the non-non-stick frying pan. I'm plannning on taking some 'instant' cheese risotto (can't remember the brand) next time we go, and seeing if Sainsburys still do ambient potato/egg/bacon/chese thigns, as they used to be quite nice. A friend recommended Look What We Found brand bolognese in a pouch, though it's pricey.
The Look What We Found Chilli con Carne is surprisingly good. We often take one for the first night if we only arrive late. Stir fry (with a bit of water) a packet of microwave rice, stir in chilli con carne packet... done. Serve with a sliced avos, tomato and some fresh parsley and you can almost imagine it's proper food - made in minutes.
I know you said she doesn't like spicy, but it might be worth trying out one of the other types.