Dilemma HO layout plan

[Canadian Atlantic Railway]

That looks very good but I do not fully understand how you will run an operating session.
Where do you start a new operating session with an engine and some cars to be distributed and where ends the session when all car are collected?
The tracks at the top right end would be useful to attach a cassette with a train for that purpose but the mainline is at the very bottom and hardly accessible to add remove cars.

I will stage the train at the start of the session. Probably 3-5 cars.