After a couple of weeks of acquiring tools, parts, and knowledge I have Old Yeller back on the road. Replaced the slipping freehub with a new one last night. Rode Old Yeller to work today. Super nice. Good tailwind home. Average speed 20 MPH.
Took several days of research to find the correct freehub, SRAM MTH 506. It shouldn't be that hard.
Whip it good
Took a while to get a 11mm hex wrench
Old and new freehub
Work bench AKA kitchen island
New cassette (SRAM PG 1070) and freehub installed
Side note: Wahoo Elemnt Bolt screen went kaput
Ride on. ☮