What do you think about the Olympus OM-D E-M5 Micro Four Third from borrowlenses.com? Can you recommend which lens to rent with it?
The OM-D is a great option, it's the best M4/3 camera on the market today. As far as lenses, for Alaska you'd want at least a wide-angle zoom for landscapes and a fast telephoto for wildlife. If you're willing to spend the money, for WA I'd recommend the Olympus 12-60mm f/2.8-4 ED or the Panasonic 12-35mm f/2.8, and for tele the Olympus 50-200mm f/2.8-3.5 ED SWD or the Panasonic 35-100mm f/2.8.
Or you could go the cheaper and more convenient way and get an all-in-one lens at the expense of quality and speed. The Olympus ED 14-150mm f/4.0 -5.6 would be a good option.