You are *G, so:

BKK - TG lounge is better (one between Pier 5 and 6, the other one, two level, towards Pier 2)

LAX - if you fly UA, you should be able to use RCC at T7

SFO - if you fly UA, again, RCC near the mid-food court.
No, you can not use SKL because you are flying domestic, as SKL is in international terminal.

IAD - there are three UA RCC I believe: near gates D4, C19 and A9 (?)