The stairway in my small cabin was built very steep, with a turn near the top, and covered with white shag carpeting. When I removed the carpeting, I found that the stair treads were non-standard (they did not have any overhang), and were pretty ugly. I was able to buy oak stair treads and cut them to fit, finishing them with stain and oil finish to match the rest of the house, and then installing them with glue and a pin nailer.
Unable to decide on a suitable handrail, I installed a temporary solution born of climbing gear and tension, and it works great and is easy to grab and get by without bumping into something solid.