I have a 2021 Vegas, but all 24.1s are the same. There is a fresh water tank drain in the compartment underneath the forward end of the passenger bed. It is a 3/4" or 1" PVC pipe that comes from the bottom of the tank and then turns aft where there is a 1/4 turn ball valve and from there it turns down and out the bottom. Open it and the fresh water tank will drain.
There are no low point plumbing drains for the hot and cold systems. You can get them to mostly drain by breaking a cold and a hot connection in that compartment or maybe behind the grill underneath the fridge where the water heater is located.
I wouldn't rely in just draining the lines. I would flush them with antifreeze. There is a chrome plated brass valve located in the corner of that compartment. Turn it 1/4 turn and it shuts off the fresh water supply and now pulls from the pvc pipe that extends upwards from the valve a foot or so. Unscrew the plug at the end of that pipe and connect a 3/8" hose attached to a 3/8 male NPT x hose barb fitting clamped to a couple of feet of 3/8" plastic tubing.
Place the hose into a jug of antifreeze and turn on the water pump. Open each fixture until it runs pink. Then put a cup of antifreeze in each sink trap and with the black and grey tanks previously emptied, dump a couple of cups into those tanks. Make sure you do the toilet and the external shower. It takes about 2-3 gallons of antifreeze for all.
The picture below shows the chrome plated valve with a red arrow pointing to it. The yellow arrow points to the pvc pipe that you connect a flexible plastic tube to. The tank drain valve is just in back of that mess of wiring and tubing.