Here’s a scenario for the Crouch Valley route, available from UKTrainSim. During the evening peak period, you’re in charge of driving a Class 315 on the London Overground service from Romford to Upminster and back. Of course you’ll be calling at Emerson Park on both trips.

Duration ~ 26 minutes
Difficulty Level ~ Easy

I’ve recorded gameplay of this scenario for my YouTube channel (which was also me testing the scenario). Feel free to take a gander at my channel if you’d like to do so. I’ve got videos about TS2022, trains in real life and plenty of other topics:
https://www.youtube.com/watch?v=aZ3Mj6SpbDQ

Lastly, here are the DLC requirements:

(Steam)
Chatham Mainline ~ London to Gillingham
GEML Class 90

(UKTrainSim)
Crouch Valley 3 – Great Eastern route | file id 32204

(Armstrong Powerhouse)
Class 314/315 Electric Multiple Unit Pack
Class 321 Electric Multiple Unit Pack
Class 377/379/387 Enhancement Pack
Wherry Lines (only the extra stock pack is needed in this case)

(Backdated TrainSim)
Virtual District Line

(Alan Thomson Sim)
Class 321 – Greater Anglia Renatus | by Clowes