Maybe a route 969 reroute?
Something like:
Woodlands to Changi Village via Woodlands Regional Interchange,
Woodlands Ave 7, Sembawang Way, Sembawang Drive, Sembawang Ave,
Sembawang Road, Yishun Ave 5, Yishun Ave 2, Lentor Ave,
SLE, TPE, Tampines Ave 12, Tampines Ave 9, Tampines Ave 7, Loyang
Ave, Netheravon Road, and Changi Village Terminal.
Or:
Woodlands to Changi Airport Cargo Complex (loop) via Woodlands
Regional Interchange, Woodlands Ave 7, Sembawang Way, Sembawang
Drive, Sembawang Ave, Sembawang Road, Yishun Ave 5, Yishun Ave 2,
Lentor Ave, SLE,
TPE, Tampines Ave 12, Tampines Ave 9, Tampines Ave 7, Loyang
Ave, Telok Paku Road, Nicoll Drive, Airline Road and Airport Cargo
Road.