To visit Mechuka, Sumo service is available from Along. From Dibrugarh Airport 450kms via Pasighat, Along. A remote area of the country, almost on the border with China. BSNL network has very weak network, otherwise no connectivity with the world. Carry cash, ATMs may not work. But the place is worth all these, its beautiful and one will experience deep serenity. Hope you enjoy the trip :-)
Also Home stays are available if you do some research, there are some fellow travellers who shared phone numbers of Home Stay owner and also the exact location of those homes.
Mechuka is gradually getting onto the top of the best travel destinations in Arunachal Pradesh. Mechuka is comparatively closer to Tezpur as compared to Tawang. You check homestays in Mechuka here: https://www.tripoto.com/hotels