New tires!!!
(5) - Michelin Defender LTX M/S 285/60R18 120H XL SKU: Michelin 46009
(5) - FITTING KIT, TIRE 04423-330
(5) - VALVE SUB-ASSY, TIRE 42607-48010
They're very quiet*, at least they're as quiet as the OEM tires and very smooth and stable.
*of course with the roof rack and awning I'm not sure I could really hear the tires anyway!!!
I'm SO close to doing this myself. Send pics.