Road no1D - Lak Sao to Phonsavan: Bikeable?

Hello,
we want to bike through central-south Laos and have found so far quite a lot of informations for our journeys.
With one exception – can you help us?!

From Lak Sao over Thasi, Thathom, Muang Khoun to Phonsavan, taking road 1D (labeled alike by world-mapping-project map), and NOT the usual one over Paksan.
Do you know that road, is it paved? Are there any guesthouse or alike, where?

Many thanks,
Kuno

I think I read a few years back that the road was closed for foreigners, military checkpoints. Try GT (Golden Triangle) riders forum, they might have more knowledge on it.