I just had five hours to kill at EWR SkyClub and Terminal B.. I did not see a single bus leaving or arriving at the terminal - and I asked ppl at SkyClub about it (going to other terminals) because there's nothing to shop in that terminal...

Maybe they time it with Lufthansa/ SAS/ Swiss/ TAP arrival/ departures?

EDIT: Actually, I don't even think any of *A flights come into the concourse that Delta flies from - and each concourse has its own security (B1/B2/B3). http://www.travelnerd.com/airports/n...l-b/40/lounges

So no you won't be able to access the SkyClub without going through the security again.