Originally Posted by AAtticus

Yes, in Bangkok, *A rules apply for the SKL lounge as well. There is no need to travel in a premium cabin to access the lounge. Just status plus flying on a *A airline gets you in the door (so eco with KF *A Gold gets you inside + 1 guest)
However in Singapore Silverkris is only for passengers in Business or higher, if you are traveling eco / premium eco but have status you can access the Krisflyer lounges only.

Originally Posted by SilverChris

You can access the *G lounges in both BKK and SIN on the basis of your KF Gold.

As noted above, it's the SilverKris lounge in BKK (along with several other partner *G lounges, if you so choose). In SIN, it's the KrisFlyer Gold lounge.