What other institutes such as these two exist for a visit by a scientist for an undisturbed period of short research? Ideally with a good landscape. Dagstuhl is another one I found.
7 of them in the USA are listed here: https://aimath.org/news/postdoc/seveninstitutes.html and there are more, for example, http://www.math.stonybrook.edu/institute-mathematical-sciences.
Not all of them have beautiful nature environment but MSRI certainly does.