I remember the PyPRP importer hanging on unconverted Myst V Ages too. However sometime it will also outright refuse to import converted Ages.
Furthermore, importing PRPs should never take longer than 10 minutes, unless you're importing a really big Age on a very old PC. It's often useful to have a look at Blender's console window (in Window->Toggle System Console): if stuff is being written in it, it means the Age is still being imported, otherwise it might be that the importer is stuck in a very long or infinite loop.
Recently I rewrote a PRP importer
from scratch, which is a bit less picky and imports more objects than the old importer. It's still WIP and I never made a guide to using it, but if you can get it to work I think you'll get better results than with the old importer.