Had the exact same situation, only a little worse, a few years back -- returned from Thor factory service in Elkhart to our then-home in Maryland, through a snowstorm that shut down the Pennsylvania Turnpike for awhile. Needless to say, the coach was coated with road salt etc., and I made a token attempt at rinsing it off before getting back to it in the spring.
What I found a couple of months later was that salt had gotten into every exterior nook and cranny, particularly underneath. The pin locks for the Blue Ox (which I normally leave attached) had completely frozen with salt, and took a lot of soaking to free up. The towbar itself had frozen into the receiver, and took hours of hammering to remove. The latch to the propane compartment (open below) had frozen up, and required a lot of work to get to from underneath and fix. The entire undercarriage had way more rust than I recalled.
Bottom line -- I'd be less worried about your finish and wheels, and way more about all the areas above. Even if you can't get to a truck wash, you can remove, clean and/or lubricate lots of things that might suffer badly from salt incursion.