I finished the section of Nikopolis.
I visited there with my husband 2 years and a half ago. It was one of the most baffling experiences that I had in Greece; many of the monuments were inaccessible, and there was no way of seeing famous mosaics. We could not even see the Victory Monument of Augustus (which is usually open, according to the local people).
Accordingly my photo archive is quite unsatisfactory.
If you plan to go there, phone them (the museum or the local tourist office) to check out what you can actually see there. You may be albe to find out particular days for the visitors!