Our Solera 24M came with a wide towel bar on the back of the bathroom door. If yours doesn't have that, maybe that's another option for you. We bought a couple of small over the door towel holders at Camping World and hung one on one of the drawers below the wardrobe (for a hand towel), and one over the door under the kitchen sink (for a kitchen towel). I know that's not the kind of towels you were referring to, but thought I'd share a couple of ideas anyway.
Larry, Paula & Bailey the Adorable Red Toy Poodle