Iceland Itinerary and Car Rental Question

I don't think that hitting all of those places across all of Iceland is realistic for the three days that you actually have for travel (assuming that the 14th and 18th are days for travel logistics arriving and departing Iceland). You should Google where all these places are and make sure you understand what you are getting into.. I've only rented a car in Iceland once, but if you rent a 2WD car you will be limited in where you can drive (mainly just to Gullfoss/Geysir and Western Iceland). If you go outside of the area they allow, your insurance doesn't cover anything. A 4X4 is a better bet if you are really determined to head out to the eastern side during the winter. You can check road conditions here to get a taste of what is coming: http://www.vegagerdin.is/english/road-conditions-and-weather/ If I were you, I would not plan on hitting Godafoss at all. It's just too far out there. Gullfoss & Hraunfossar are both a little out there, but still in the most populace area (and the biggest tourist destinations) so you should be OK there if you are OK with winter driving. Seljalandsfoss & Skógarfoss should be just fine since they are on the ring road. Fjallfoss might be better with an overnight somewhere up there, as opposed to trying to do a day trip there. During the summer, all of these would be AOK.. but I am not sure how I would feel about heading there during the winter.