Welcome to the JOF! Somewhere inside a cabinet, or behind a removable panel, there'll be a "whole house" water filter. It may be already bypassed when it was winterized, or they just removed the filter cartridge. Find it in your coach and see what they did, so when you hook up a water hose to the outside to flush out the antifreeze from the system, that filter canister gets flushed out completely as well, if it's full of pink stuff.
Make sure all the low point drains are closed. With water hooked up to it, open all the faucets, the shower, flush the toilet, and the outside shower too. When the water runs clear, it's de-winterized. After you do that, you'll have to switch the water heater bypass valves so it will fill with water. Hopefully it was bypassed so there's no antifreeze in it. That would require draining and rinsing out if it wasn't.
You may want to sanitize the plumbing with a bleach solution. That should be covered in your manual.
Every day's a learning experience, though sometimes not what we expected.
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1 Spoiled Dog