I'm going there this year. Three years ago I tried fishing fishing off the back of the boat. I did manage to hook a few good size trout. (3 - 5 pounds)
Problem was I did not have a down rigger. I used the sliding lead weight. Using an apex lure, let out about 100 feet of line and then attach your sliding weight. At trolling speed your trying to get your lure down to about 20 feet.
The best times were early in the morning and later in the evening. When you do hook them, your in for a pretty good rodeo. Thats when the sliding weight becomes the problem. In my case the fish through themselves off the hook.
I'll see if I can get my hands on a down rigger this year. Better depth control and once it pops its just you and the fish.
Good luck on your trip. Here is a link to show you what an apex lure is. The water melon one worked for me.
Ed S.
http://www.hotspotlures.com/products_apex_troll.php