You could try Kumaoni cuisine for lunch/dinner as travellers like to experiment with the regional cuisine.
for breakfast you can put options like variety of paranthas, poha, upma, idli, etc
also you could ask your guests what they would prefer n put up a mixed platter with their n your choices
Please let me know where is ur cottage near nainital.... And about breakfast or lunch you have to ask from the travellers first because everyone has own different taste...
Well as per my opinion, Varietiy of Paranthas, Poha Vermicelli, Idli, Dosa . these are some forever options....
I think it's best to ask guests what they want and from your side you can give breakfast options like maggi, sandwich, poha, idli, chilla or any speciality of your location which will not take much time to prepare. In other meals also do the same, give some common options and some of your local food.
All the best!!!