Route 4 hiking option in Jinshanling Great Wall.

1. Yes, you will exit on the east gate after finished the Route 4. If you wanna get back to the middle gate, you have to go back to Small Jinshan Tower first and then take the cable car to arrive at the middle gate. This way is complicated and inconvenient.
So just take Luanping-Beijing intercity coaches from the parking lot (the Service Zone of the scenic area) nearby and get back to downtown area. The walking distance from the East Gate is just about 0.6 miles (1 kilometer). BTW, the service hours of the bus line are from 6:30 to 16:00. It costs CNY 32 per person for the whole trip.

2. The map doesn't mark the Kylin Screen Wall on this page. It is on the 2F of a beacon tower named Small Pot which closes to Bricks with Characters Scenic Spot.
Hope helpful!