Re: High lakes above Mammoth
CF guy, welcome!
Go as light as possible, bit of a hill climb at the start. I think a bear can is required now, you can rent or buy, it does add weight.
In early June it may be a bit chilly this year, but fewer mosquitos then.
I would get on the trail very early, you will hike in the sun for a ways, until you get over the first bench. Later when it is very warm, I do it at night, cooler to hike with a pack.
You will see small Hoppers lower down. The guys up above will eat them too.
Hopper dropper is worth a try. Have a few that match the local bugs, some extras for the bushes too.
Small is good in high pressure areas. I might take a sink tip to fish the drop offs.
Vsmall minnow pattern, leech, etc. Fish the structure, boulders/logs.
Cast an indy into the creek, then let it drift into the lake.
Should work. Try different retrieve rates, from near motionless to fast, and everything in between.
You'll need water filter. Maybe apply early for BackCounrty permit. Otherwise, first come first served at ranger station. Give them a call.
Nice area, enjoy!
"Life's too short to fish poorly".