There's a highway that takes you all the way to Tezpur. If you want to proceed ahead into Arunachal Pradesh (if you're visiting Itanagar, Ziro or Tawang), you need to apply for the Inner Line Permit here. We would've loved to set camp for the night in Itanagar, but we reached Tezpur late afternoon, and the permit would be issued only in the evening.
We decided to instead take the road along the Assam-A.P border to Lakhimpur, the next big town. Unfortunately, it started raining when the moon came out, and the bike began slipping on the wet, gravel-filled roads. We stayed for the night in Banderdewa, a border town.