What is the recommended wire thickness to run between 125-150ft to a detached shed (home office)? I was thinking 60 amp breaker, 4/3 thwn-2 (2 hot, 1 neutral, 1 ground). Do I need more?
#4 THWN aluminum is exactly what I'd use.
As far as voltage drop, 150' isn't far enough for voltage drop to become a concern. I don't even run the numbers until 180' :)
#4 THWN aluminum breakers at 70A (it's rated for 65A but you round up to the next breaker size which exists).
Because it's capable of 70A, you need a 70A ground wire, which is #8 copper or #6 aluminum. If aluminum, it must be insulated. You're allowed to use #4 aluminum, and the benefit is that you get to use black wire and mark it green with phase tape. #8 or #6 ground would need to be actually green or bare.