One thing you need to know about Alaska is that the areas you're planning on visiting can have prolonged "rainy" periods, but the actual amount of precipitation is not all that much. In Anchorage it can rain all day and only have 1/4" of rain. Kenai is a little bit wetter, but it is usually pretty easy to dry out. The humidity is generally quite low. I've done plenty of hiking in the rain without any rain gear at all. Polypro is nice to have... dries quickly while you're still wearing it. Seriously, you don't need expensive rain gear here... the rain doesn't care, LOL! You might actually get more mileage out of a softshell jacket to tell the truth. I have close to a dozen of them now. OTOH I only have 2 raincoats and I rarely use them now.

MNS

Edit: LOL, I counted my jackets - 9 softshells, 7 smooth outside, 2 fleece outside, and 2 rainjackets - a Sierra Designs packable parka and a GoLite that has been discontinued for many years now (can't remember the name). The GoLite (my favorite) was originally over $100 IIRC, but of course I didn't pay that much for it.