The logic that's being questioned is buying a truck with fairly unique and rare conversions on it (M-H 4WD and SnoGo blower setup), and then turning it into a 2WD truck to drive down the highway while expecting it to be a "bolt-on and go" type deal. In that case, what's the point of having something with the aforementioned?
You seem to be fixated on something that's a "direct bolt on", when options have been laid out to allow you to keep the M-H conversion but use a more modern and friendly transmission. Yeah, it'll be a bit more involved, but isn't part of the "passion" figuring that sort of stuff out?
How much have to driven the truck so far? You seem to be too concerned about double-clutching when the main issue is the really getting it up to a road speed that's appropriate for your intended usage. After a short while the double-clutching will become 2nd nature and not that big of a hassle or problem.