yummmm...coconut milk! If it appeals to you, you might try looking into Thai food for some richer meals. Some of the Thai curry mixes (easy to find at most Asian markets or try looking online) are vegetarian and Thai curry is pretty easy to make. Thai stir fried noodle dishes would be good too - use a good oil to stir fry in, add lots of bean sprouts and crushed peanuts ... yum! You won`t be using fish sauce, of course, but you can add some non-wheat soy sauce and/or a wheat free Chinese stir fry sauce to add some of the fermented-food-complexity that fish sauce provides.
In cutting out dairy, in addition to adding the coconut milk I would add a lot of nuts and seeds. You could do simple things like add a handful of almonds to your breakfast or you can look for ways to add them to your meals. Toasted sesame seeds ground with a little salt is great sprinkled on rice - that will add protien, fat and calcium to your meal.
Japanese food is a good source of gluten free meal ideas (assuming you have found a wheat free soy sauce) and because a meal often consists of several dishes, many dishes are vegetarian. You could look for a Japanese cookbook or find some recipes online to get some variety in your diet. I think Japanese sesame dressing would be a good addition to a diet like yours, and miso soup is an easy vitamin B rich and probiotic-ful addition to a rice and veggies meal, as is a dip made from roughly equal parts miso and honey. When you are making rice you can add some extra calories by adding a little salt, a splash of sake and a splash of soy sauce and handful of walnuts or peanuts. Lots of yummy tofu recipes to be had, as well. If you are hungry and don`t object to deep frying, try to find a recipe for "age dashi dofu."
If you are needing calories at this point, you might consider replacing some of your brown rice with white rice. I know lots of people object to white rice because of its refined-ness but you can eat more calories in a bowl of white rice than in a bowl of brown and in my exoerience, if the rest of your meal provides the nutrients you need in the form of low calorie veggies, I need a decent amount of rice to provide the accompanying calories (rice or another starch something, but for me here in Japan, it is most often rice). You can cook a mix of brown and white rice, as well, or add to the variety by cooking some millet with it.
long post, hope something in it helps! I eat a vegetable and rice based diet with small amounts of meat and fish and very little dairy, and I remember how hungry I was when I first went GF. good luck to you!