With all due respect, I disagree about the ultra wide lens. The very wide angle lenses (even the fish eye lenses) are indeed very good for landscape photography. It is true that a long lens can also be quite effective for landscapes too, but sometimes one cannot step back far enough to get the composition you might want. Super wide angle lenses are not indispensable, but they sure are nice to have...You go on a trip to Iceland and take only the 14-42mm lens? I'd say you didn't put much thought into your trip. However, that lens alone should have met most of your needs shooting landscapes. In my many years of experience many people make the mistake thinking an ultra-wide lens is needed to shoot landscapes. About 99% of the time taking a few steps back can solve the FOV problems you may think you have. Not to mention the potential of stitching.
On the long end a 45-200 zoom would have done the rest of the work for you. And not a very expensive lens to boot.