Do not take Hwy 66 to K Falls,steep drop offs with no grad rails along with a lot of steep twisting road. Go to Hwy 62 from Medford to Hwy. 140 to K falls or Hwy 62 to 230 to 138 to 97, AT Medford take the Crater Lake off ramp Ext 30 go north. Hwy. 62 or 140 are good roads and lots of big rigs and RVs take it all the time.Check your map and you will see what I'm telling you! I live in the area and travel those roads all the time. Gas up in the Medford area before you leave the area.
I see that you need to go to Klamath Falls so take Hwy 140