I would just start with basic safety equipment, a bow mounted trolling motor and battery, and seats. You can add more this year as you break it it. It's also always good to have an anchor, never know when you will need to hold position.
Specific to the Grizzly, they have some kind of track...
Having been twice I would recommend at least two rods. The 5 weight mentioned above as well as a 6 weight if you encounter windy days (very likely). You also want some insurance of a spare rod on a trip like this.
We did very well in the Twin Bridges area - several different rivers you can...