Although TfL produce a map for 60+ London free travel on National Rail, I have been unable to find a bus map which clearly identifies how far from Central London the 60+ London Oyster Photocard is valid and which bus routes are applicable?
For example, buses to Bluewater Shopping Centre such as the 492
Buses from Ewell East to Epsom:
S2 bus to Hessle Grove
E16 bus to Epsom Clock Tower
Buses are zoneless, so if a bus accepts Oyster then it is valid for the whole route. The 60+ Oyster is accepted on all TfL bus routes after 9am on weekdays.
It’s definitely valid on the 96/428/492 to Bluewater. If the other buses you mention are operated on behalf of TfL and accept Oyster for payment then it will be valid on them too.
I use TfL Journey Planner for travel instructions and I was advised to leave the S2 bus at Hessle Grove to catch the E16 bus to Epsom. Unfortunately Journey Planner can be quite misleading if you are unfamiliar with an area.