A large majority of the fishing we do in freshwater is done with a floating line with a 9' leader and weighted flies. A good front loaded weight forward line such as the Rio Grand is a great all around choice, especially when chucking the heavy streamers used in Alaska. Lines like this are versatile and can be used with a short 4-7' attachable sink tip or poly leader if the weighted fly isn't getting deep enough.
There are situations where a floating line, even with the aid of a poly leader do not cut the cake. In these situations, having a spare spool with a integrated sink tip line is ideal. These lines can have sink tips that vary in length and sink rates. Rio makes two series of freshwater sink tips. The Streamer Tip is a front loaded line with a 10' Type 6. We're finding this line to be a great choice when using it with really heavy streamers like Dolly Llamas and Hareball Leeches. Rio's DC 24' Sink Tips are great choices for fishing big rivers, lakes and even saltwater. The 300 grain is a good choice for a single hand 8 wt.
Not sure where you will be fishing or what types of water. Check out the Rio Versi Tip or the custom Super Versi Tips. These lines are a great choice for the "One line to do everything." The standard comes with interchangeable 15 tips (floating, intermediate sink, type three and type six sinks.) The Super Versi is supplemented with MOW Tips to for when a 15' tip is too long. These lines are great investments for Alaska fishing when there isn't room to pack a spare spool.
Leaders and Tippet:
With a floating line, we typically use the standard 9' tapered leader and tippet to match. For most fishing we recommend using Salmon/Steelhead Leaders and matching it with Maxima Ultragreen for tippet when needed. This leader material is stout with a larger dia to breaking strength ratio. This is good for helping turn over large flies when fishing to salmon or swinging flies to trout and char. Trout leaders and tippet is good for fishing dries and nymphs to grayling and trout in the early season. For bead fishing, we recommend using fluorcarbon, or a mono leader to fluorocarbon tippet.
What flies to use when and where? This is probably the hardest question to answer because of how big and diverse Alaska is. The best thing to do is to contact us and we can make the best recommendations. We also offer some premade fly selections. One is called the Alaska Highway Selection which carries a little of everything. This could be a good choice for the traveler going everywhere.
Best of luck and we hope to see you on the water!