Should be practical enough to carry both systems, even in an airline carry-on, provided your 4x5 is itself light and compact. But even though I've never been to Iceland itself, I'm willing to bet the determining factor in how much use you'll get out of one or the other will depend on the wind. And in my experience, there have been plenty of times in treeless areas where the wind has been so intense that I had to resort to handheld shooting. But then an opportunity opens up where the larger size of sheet film and its plane of focus movements make it worth every bit of the extra effort.
But carrying too many lenses, backs, and just too much sheet film??? If you save 4x5 exposures for just the most special shots, and trim down your kit somewhat, yet with room in your carry-on for a collapsible yet really solid tripod, I think you'll have a more enjoyable experience. The quality of shots is way more important than the sheer quantity. That's how it look at such opportunities - but I'm no machine-gunner, and never want to be; couldn't afford to be anyway. I'd rather come back with two classic 4x5 shots rather than a thousand ordinary ones. If they aren't worth printing, they aren't worth shooting. Being under constant pressure to shoot and shoot takes away from the travel break and turns it into another chore. Take some time to just soak in the light, and then press the shutter when it feels downright compelling.
Bookmarks