Never been to Alaska, but find shorter barrels pretty handy here in GA where it can be pretty thick.
The velocity loss isn't nearly as much as most people think. No where near 50 fps, even for magnums. The difference between individual barrels is very often more than 2" of barrel makes. I've seen 130+ fps difference between two different 22" rifles shooting ammo from the same box . My Winchester is consistently 90 fps faster than my Remington, both with 22" barrels. I could cut 4" off the Winchester and it would still be faster. My 20" 308 is the fastest shooting 308 I own. It is 15-35 fps faster than the ones with 22" barrels.
You're going to lose speed when cutting the barrel back. And more from a magnum than from a 308 or 30-06 class cartridge, but there are numerous examples out there where people have done this and documented the results. The largest documented velocity loss I've found was 70 fps from cutting 2" off a 300 WM. Most cartridges are in the 10-25 fps/inch range.
And even then at under 50 yards you're going to be hitting game with faster impact speeds from a short barrel than a longer barrel would at 150 yards. If the rifle is adequate at 150 yards from the long barrel it certainly will be fine at under 50 from the shorter barrel.
Short barrels can be loud, and may not carry and balance well. But I'd base my decision on those concerns rather than a few fps of velocity. If you're planning on shooting at 1000 yards, then an extra 50-100 fps might make the difference.
