I had heard a lot about Fort Portal with its towering Rwenzori Mountains before I got there but nothing prepared me for how grand they actually are. The crater lakes are stunning too! Drive out to Semuliki National Park, it's worth it, and make sure to visit the Amabeere ga Nyina Mwiru caves.
Kahama is usually a place you pass through when you are going somewhere else. It's a handy place to spend the night on a long road trip across Tanzania. I've had some pretty fun nights in Kahama though.
I cannot imagine what you would be doing in Bulyanhulu unless you are from around here or are somewhat affiliated with the gold mine. If you are affiliated with the gold mine then this is a pretty fun place to be.