It seems that vehicles operating in deep snow or unfrozen tundra involves a lot of trade-offs, ultimately ending up being particularly specialized or the boy scout knife of vehicle; doing a number of things sort-of well but none of them really well. The Sherp seems capable, but slow and relatively small.
Even in exploration world, they typically have pre-determined destinations and wait until freeze-up and prepare the route with bulldozers. The 'rig-handling trucks, while very capable (powerful, good clearance, multi-wheel drive) don't operate on unprepared ground that I am aware of.
I think though, that Prairie Canuck is offering you two choices:
You can go anywhere slowly.
Or you can go some places fast, weather permitting.
In deep snow, bush, muskeg or at spring break up nobody is going anywhere fast. As Vlad is finding out. Even in the prairies farmers have to pick their opportunities to get on the fields. A little bit after the frost starts coming out of the ground but before spring meltwater and rains turn the gumbo back in to the saltwater marsh it used to be.
Surface travel is likely going to be restricted to walking pace, or a little better, with the vehicles being used to transport heavy gear slowly.
If you want to move fast then you are going to have to leave the surface, either by aircraft or helicopter.
Or, along highways.
Which brings me to a direct question for Prairie Canuck. What is the primary means of transport for those Foremost vehicles? An F350 and a beavertail or a low-bed semi?