First, good luck finding a Ruger Alaskan in 454 Casull. They are catalog items, but there are none in production. You will need to scour gunbroker.com and gunsamerica.com for one. Be prepared; they're going for around $1,000-$1,100.
If that's the case you could get a S&W .460 ES for about the same price. Shoots not only the .460 Magnum, but .454 and .45 Colt as well. The massive X-Frame will help a little with recoil too. From my experience, the .454 many times is put in too light of revolver and the recoil is thus......brutal. For bear protection the second or third shot is just as important as the first. Good accurate follow up shots are easier to obtain from a gun that doesn't kick like a Clydesdale.