Winterize, winterize , winterize....it costs under $10 of antifreeze, doesn't take long, and you have peace of mind. What if a cold snap comes, and it could if your gone for 2 weeks, unless you really trust the weather people
... If you drain the water, there will still be some in low lying spots, and what if they get a hard freeze and you are up in WA....nothing you can do and the headaches you will have after will have you cursing for a long time...if the forecast is decent you may consider blowing the lines out with pressurized air, and skipping the antifreeze, but that totally depends on whats in the forecast. If you do use pressurized air, be sure your compressor isn't putting out any more than about 40 psi., otherwise you may create further problems.
To drain the hot water tank just remove the anode rod...if it doesnt have the anode rod it will still have a plug in the same spot....first relieve any pressure in the tank with the pressure relief valve on the outside of the tank. If you decide to use antifreeze, remember to turn bypass valves on hot water heater so you don't fill it with 6 gal of antifreeze.
There are many Youtube videos showing all this, just do a search for Winterizing an RV. Winterizing really isn't difficult, and if you own an RV, you should get comfortable doing it, you learn a lot about your systems at the same time, that can help you trouble shoot in the future.