You can take a bus from Barking to Waltham Abbey via Loughton Station in around 1 h 22 min.
How to get from Barking to Waltham Abbey
From Barking train to Blackhorse Road Underground Station, Tube to Tottenham Hale, then train to Waltham Cross. 41 min £8. From Ilford, High Road Ilford line 167 bus to Loughton Station then line 66 bus to Waltham Abbey, Bemor Builders. 1 h 22 min £6. From Barking taxi to Waltham Abbey. 22 min £83. From Barking drive to Waltham Abbey. 22 min £3.