Walkaround lens recommendation for D5100?

I'm going on an Alaskan cruise this summer and I'm looking for a decent , but ultimately cheap, multi-purpose walkaround lens. I'd prefer not to be lugging around a kit, but I also don't want to miss the photo-ops that are likely to arise. (likewise, I don't want to be worrying about falling on a $1500 lens while hiking along a glacier). I don't mind tossing a fast primary in my pocket for the occassional indoor shot (the wife can hold the other lens for a few minutes while resisting the urge to beat me senseless with it). I'll probably leave the "walkaround" in the cabin in the evenings and stick with a 35mm f/1.8 in for evening shots around the ship.

Any suggestions would be greatly appreciated. I'm having a hard time finding the right balance between the wide vistas and distant wildlife in a single lens.