End of the road.
It turns out the Winnebago was not that great of a deal after all. 3 cylinders were misfiring under load (bad plug wires/boots) and one not a all, so we though that might be the cause of the knock, but it was not to be. When we changed the plugs, one wouldn't go back in. Upon closer inspection, found a hairline crack in the head. Blown exhaust manifold gasket heated the head unevenly, binding an exhaust valve and (I'm pretty sure) breaking a lifter. So Winnie is done for now.
A couple friends (God bless 'em) are on their way, driving 2400km to bring me my van and haul the motorhome back. It's just not worth putting the time and money into an engine that leaks out of every seal with exhaust manifolds that are stuck on (already had two broken bolts.) So I figure if I don't have to drive it over the continental divide, I should be able to limp it around home for years to come. Or sell it to someone who wants to do the same. Or maybe I will fix it. Who knows.
4000km Cassiar/Spatsizi/Telegraph/Alcan fish and ride here
What you're Missing: a Guide to Side Trips off the Cassiar here
Canada's Best Kept Secret: 500 km from the nearest paved road here