I never actually went in the bathroom so I'm not sure. I don't think there's a dishwashing sink so I would take a basin or bucket and use that- there are water spigots at the campsites.
If you are actually staying at holder mine campground with electricity and water, yes they have regular flush toilets and showers. If you are staying in one of the primitive sites that are near there they are vault toilets and mobile outhouses.
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