flying past Mt St Helens en route to the eclipse in idaho aug 2017

Departing Chehalis KCLS for Midvale Idaho to view the solar eclipse Aug 21, 2017. We found a gap just NE of KCLS and climbed through to fly just above the scattered clouds and past Mt St Helens where the clouds cleared for a CAVU flight to Midvale 2 hours away. No smoke haze until we crossed the snake river and even then it was tenuous. It was a very different story on the way back. On our return there was a thick smoke haze inversion layer over much of Washington State en route getting quite severe as we approached the Cascades with in inversion layer above 8,000ft and 20 miles visibility below.