Yeah, I've got the glass, just not the practice!
Taking the monopod and tripod, although I doubt either will do much good in the boat. I imagine I'm going to have a lot of blurry stuff until I get some settings figured out... This stuff's a lot different from taking photos of guys on a firing range or going through training exercises!
The monopod may help, if just as a way to rest the camera while keeping it "at the ready". I've never done a float trip, so you'll have to try and determine whether it's better to hand hold, or to use the monopod resting on the floor of the raft. I doubt you'd have room for a tripod, but it could come in handy while on shore.
As for the settings, here's my suggestion:
1) Set the ISO as high as you're comfortable with. Unless you've got a really nice sunny day, that would probably be something like 800 or even 1600 if your camera has decent quality at that range.
2) Set the camera on aperature priority, and use the smallest aperature you can. Shallow depth of field will help isolate your subject, the eagle(s) from the background, which is typically branches and other clutter.
More importantly in this situation, it will help you get higher shutter speeds. I feel that the real priority is having a fast shutter speed, but I get there by shooting wide open. That way, I get the fastest shutter speed conditions will allow, and if the light improves a bit, the shutter speed will go higher, which is a good thing. If the light goes lower, I've already got my other two setting maxed out, so at that point I have to decide whether to up the ISO or go with a slower shutter speed.
You can, of course, do it the other way and set the shutter speed. It's all a matter of personal preference.
3) Check your shutter speed. I'd suggest trying for a shutter speed of 1/200 or faster, considering you're on a moving raft. The faster the better. If you're lucky, maybe you can get a bit faster than that.
Once you see what the shutter speed is, you can adjust the other settings as needed. On a dark and grey day, you may have to up the ISO. I was shooting at 1600 part of the time when I was there. I didn't like that, but a grainy but sharp photo is better than a blurry shot with less grain.
It's all a balancing act. If you've got bright sun, you may be able to drop the ISO a notch or even open up a stop. On the other hand, a faster shutter speed won't hurt anything, and may well help you get sharper shots.