I'd go with a 8wt if you want to buy another. It's seems like the perfect all around Alaskan weight for many. You don't need to spend a ton of cash. My second trip up there I chased silvers and rainbows on a $80 8wt. St. Croix Premier. The trout didn't seem to hold it against me and it performed great. You can get a 4pc now for around $110.
I'd reccomend bringing a fast full sinking line and some good streamers like purple or black egg sucking leeches with some good flash on them(size 6). Even though eggs and flesh patterns work great I've often had better luck chucking streamers. Bring some smaller streamers as well in case you find yourself where grayling are saving the day.
My first trip up there was a road access only trip like yours and it was a learning experience. I'm sure your guide will be able to take you to less hammered areas but prepare yourself for Alaskan Combat Fishing. Since that trip I've always spent the extra money on one more commercial flight from Anchorage to various roadless towns and a bush flight to some solitude. 100 people nailing the same hole just isn't what fly fishing is about to me. Just a heads up. Enjoy your trip! I'll be up there too this August/Sept chasing Charr way out in the middle of nowhere.