A typical MC simulation of water makes small incremental water moves, with correspondingly small energy changes, and thus can have a large acceptance probability for these moves. In contrast, here the whole point is to make large translational MC moves that allow jumps between the protein cavity and the surrounding water. This leads to a rather low acceptance rate and motivates efforts to maximize efficiency. Following the marked advance in speed described here, possible future directions may include omitting moves that would be only within the surrounding water or within the cavity, as these are not very interesting and are accounted for by the MD steps, while being careful to avoid any possible violations of detailed balance. Another direction is to allow small clusters of water to move together in order to increase the rate of acceptance for moves into large nonpolar cavities. However, the present method is already highly efficient, and is currently available for use in the AMBER simulation software.