I fell in love with this area back in the late 1990s.
Ridden many routes - driven others.
First off -
Hwy 140 from Klamath Falls to Beatty is not the best choice - esp with youth.
Narrow, few shoulders, moderate+ and fast traffic, blind hills and curves.
You can take the OC&E Trail out of Klamath Falls - first 8 miles paved, then gravel.
One of the most beautiful rides in the region is along the Sprague River - from Chiloquin to Beatty.
From Klamath to Chiloquin - US 97 has shoulders but very heavy traffic - West Side Road is better.
East of Beatty, Hwy 140 has less traffic, but still pretty high speeds amd little shoulder.
Instead of Hwy 139, you can loop south from Merrill and head thru Lava Beds NM.
Since much of this loop is heavily forested, the open vistas are a treat.
Further south on Hwy 139, you can take Lookout Road to either Adin or Bieber.
Almost no traffic and you miss the Hwy 139/299 section which is a little busy at times.
Eagle Lake should have plenty of water after two wet years - great desert lake.
I love US 395 in this region - wide open and remote - like Nevada.
There's a back road east out of Susanville to Litchfield - country store.
I can't remember if the Termo Store was open when I went thru. Be good to check.
The east side of the Warner Range is awesome - Surprise Valley Road
No good way to get to Eagleville without dirt - so it may not be possible for y'all.
Fandango Pass Road is hardpack - big climb coming from east then great downhill to US 395.
Lakeview is a friendly town - Hunter's Hot Springs north of town has pools and camping.
Best - J