I hunt squirrels and a kill a doe/year with a rifle. It (rifle hunting) is different and I enjoy it. However, the vast amount of my time is spent bowhunting because of the extra challenge and tremendously long seasons. Personally, I would not take the rifle. I'd make sure the terrain and the guide were well-suited for a high probability of a bowrange encounter with a moose. Here's the litmus test I recommend. If you kill the moose with the rifle, when you are describing the hunt to your buddies (post-hunt story-telling is a big part of the enjoyment of hunting for many folks) will you have a bit of an apologetic tone for having killed it with a gun or not. If so, don't do it. By the way, I'm not suggesting the moose, the hunt, or the hunter is a bit less or more based upon the equipment used to take the animal. It's all about what winds your clock.
In 2008 I sort of got "trapped" (long story) into an antelope hunt recommended to me by a collegue. My buddy and I took our bows, no rifles. The rut was over, they weren't using waterholes, and the terrain was terribly open for getting close. We ended up borrowing my friend's son's rifle to fill the antelope tag. The son flew in to Casper to rifle hunt. We were excited at the time and I don't regret taking the animal. However, I still feel like I didn't get er done on that hunt. My poor planning was the culprit. Irony -- we put the son in a ground blind and I sort of "drove" (walking) some antelope along a fenceline right to him -- his first bow kill was a buck antelope and we had to fill our tags with his rifle -- he sure had fun rib'n us, bless his little stink'n heart.
I just contacted a NFLD moose hunting guide by doing a search on Google. He sent me an e-mail right away with prices and a description of the hunt (7-day hunt - $4,500 for 1 on 1 hunt a bit less he said for 1 guide with 2 hunters). $5,500 for "trophy" hunt of 10 days. I was surprised it wasn't much more. Of course I'd have lots more investigation to do before selecting a guide. This wouldd be the first time in 45 years of bowhunting I would hire a guide. I'll be checking with my buddy who is going this fall (I'm planning 2011) because personal reference is what I'd trust most.