I'm headed up to Lake Clark National Park in late August. For those that have been up there that time of year which prime do prefer? 300, 400, or 600? I will also have my 50-150 packed for the wider scenes.
I was there last year. If you are photographing the costal brown bears, they may end up a lot closer than you expect. They sure did for us. Our guides would position us and they would approach as they were feeding. I had very few images at a focal length over 400mm. If I had it to do again, I would pack the 300mm f/2.8. I had my 200-600mm last year, with other lenses. I would take my 300 f/2.8 along with a 70-200mm f/2.8, 1.4X, and 2.0X converters if I went again.