(concord 05) Your post jarred my brain. I winterized last week and never even thought about the low point drains.. On every other RV I've had they were easy to spot but I've been under this one a number of times and never seen them??? So this afternoon I crawled under there again AND found one of them!! If your layout is like mine (sink on the driver's side just behind the wheel well) then you will see the small drain pipe behind the rear wheel well.. it only sticks out about an inch. Only one of the two drain pipes is visible.. I think the other is hidden above a small storage compartment.
To get at them you need to pull off the grill under the cupboard door that is below the sink. You can also see one of them if you pull the drawer(s) out.. but you will need a flashlight. I don't think pulling the drain valve is really necessary since there is no water in the end, like there would be with the other type which has a drain cap. These do not have that.. they only allow water to drain out of the line that is blown out or that has anti-freeze in it. I have taken some pictures but don't know how to post them on here. Send me a PM with your e-mail address and I will be happy to forward them to you.