Hang on; I don't want just any Wagon. Make mine an all-stock '62-'65 model with the factory 230 inline-six. I'd hit the distributor upside the head with a Petronix electric ignition conversion and replace the carburetor with a small two-barrel TBI injection system. After rebuilds, the stock T-90 could stay in front of the Spicer 18 T-case, but I'd toss a Saturn Overdrive in it.
I'd hang a Saginaw manual steering box off the framerail and connect it to a pair of wide-track offset Dana 44 axles from a '79-earlier Cherokee Chief. Or a Wagoneer, depending on how wide the stock Wagon axles are...I can't remember. The 4.88s would ride open carriers.
Inside I'd reupholster the factory front, rear, and way-rear jump seats and hang 'em over the redone chrome and hardwood floor inserts. No carpet for me. The rear windows would get tinted so the Vintage Air A/C system didn't get overworked. Add some skinny 16-inch rims with some pseudo-modern A/T tires in a 255/75R16 size and I'd be stylin' for my So Cal commutes. With the Warn Overdrive and the 255/75R16s 'd be buzzing along around 2,600 rpm at 70 mph. Right on the ragged edge of livability for the 230, but no guts no glory.
Outside would get resprayed in vintage VW Pamapas Green over Cream. I can't decide if I'd go flat or gloss. Naturally, some dog dish hubcaps would hand on the steelies and would be polished to match the mirror chrome and stainless on the body.