It's your last airplane checkout, and it's a big one. Literally. For your training flights in the Boeing 737, you're going to fly from Los Angeles International Airport (KLAX), one of the busiest airliner airports in the world.
This flight puts your Boeing 737-800 on the south side of the airport at our "training center". En route flight in a jet is boring and is usually done with the autopilot anyway. No need to practice that; instead, you want to practice the maneuvers you'll do when departing and arriving at airports. You'll also want to fill out this profile matrix. It's a bit trickier to get profiles with large planes because weight is such an important factor in performance.
After you fill out the rest of the profiles matrix, slow to about 220 knots, and practice the maneuvers you usually practice with a new airplane: steep turns (45° bank is all you need to do), recovery from unusual attitudes, and approaches to stall. We don't do full stalls in jet airplanes, Instead, you should recover the airplane at the first warning of a stall. You should do three types of stalls: one in the takeoff configuration (gear up, fl aps 5°), one clean, and one in landing configuration (gear down, flaps 30°).
Ref.: West, Jeff Van. Microsoft Flight Simulator X For Pilots: Real World Training, Wiley. Bonus Chapter 2 - Air Transport Pilot, Boeing 737 (Page 760).