Alternately you can ride to Hot, then Mae Chaem, then to Doi Inthanon, and come out at the upper security checkpoint, then down Doi Inthanon with no hassles, have done this at least four times, the last time was 2 weeks ago, great loop, with lots of variable road conditions!
........or, if you have a Thai drivers license you just pay the Thai entrance fee which is minimal. Don't be a "cheap Charlie" Fabrice ! I think supporting the park with the Thai fee is reasonable. It's the double pricing Falang fee which is objectionable.
My buddy and I rode Doi Inthanon last Wednesday. No problem getting in the park at the Thai price upon showing our Thai Driver's licenses. This time they were very diligent about checking our tickets upon leaving the park at both ends. That is a change.
The first section of road is getting pretty rough. After several kilometers it smooths out nicely. Our first stop was for a very pleasant lunch at the Royal Project. Continuing on... The road to the top, after the second checkpoint, is now getting readied for a long overdue resurfacing. Lots of gravel about, so proceed with caution. Should be a treat when they are finished. At the top we had our usual cappuccinos, which were quite welcome since we were socked in with heavy clouds.
Back down the way we came, we were treated with a very intense downpour and lightning. Guess that was inevitable, having decided not to pack the rainsuit. Good to get out and about for a change.