I am thinking of heading up to Nam Nao national park soon. I can find numbers for forestry commision run huts, are they ok ? Has anyone stayed in or know of any other accomodation in or near the park ?

In my experience official accommodation at NPs can be either great or dire. Its really pot luck.

The park is easily reached from Lom Sak, Petchabun or Chumpae al of which have decent hotels there.

Have you thought about camping? Tried it with a few Thai friends earlier this year in Nam Nao and had a great time. Nice and cheap too to hire all the gear in the park.