To my disappointment, Tower Falls was not available during my visit. Nor was Gibbons Falls - both due to construction.
Rustic Falls, north of Mammoth Hot Springs, is quite nice. But it is north facing so the sun never hits all of it. It is best photographed on a cloudy day for even light.
Another waterfall worth checking out is Undine Falls, in the north section of the park. This might be a better autumn picture.
Sunny days are best for geysers. Mostly blue skies allow for contrast and definition of the eruption. Overcast days cause the plumes of water to blend against the cloudy sky and detail is lost.
Obviously, you don't want to be shooting in the direction of the sun. Likewise, you don't want to be down wind of the erupting geyser! Understanding the direction the geyser will erupt will allow you to plan your composition, rather than be reacting to the elements.
Know the estimated schedule for each geyser's eruption ahead of time. This will put you in the best possible position to succeed. Schedules are available as handouts at the visitor center, posted at most of the geysers, and available on the park's web site.