If it were me there'd be no question: 70-200/4. It's light and small (relative to 2.8s), sharp as all get out, long(ish), and relatively affordable. On a crop camera that's 300mm of reach -- still not quite a "pro wildlife" lens, but not bad at all. The 70-300 lenses I don't think to much of. But the 70-200/4 is a superb lens.
dh: at this point you've probably over thought the possibilities given the situation you described. Bottom line, there is limited cash and more equipment desires than wallet fodder - don't we all have this problem Buy the best glass you can, hopefully an L. A used 70-200L f/4 is most likely your best bet. Then go enjoy yourself in Glacier, its a wonderful place to spend your time.
Buy the best glass you can, hopefully an L. A used 70-200L f/4 is most likely your best bet. Then go enjoy yourself in Glacier, its a wonderful place to spend your time.