The 2006 Sixth Doctor story The Nowhere Place isn't bad despite having been written by Nicholas Briggs. Briggs, who voices the Daleks and various other things for the television series and the radio plays, generally doesn't write anything good--maybe that's the reason he's never been asked to write for the television series. But then we'd have to account for Mark Gatiss. But The Nowhere Place is nice and eerie, the Doctor and Evelyn--and the presence of Evelyn always elevates Six's stories--find a peculiar doorway on a spaceship. People are drawn into it by the sound of a bell that comes from a 1950s steam train and, when they walk through the door, they're killed by something. It has so many of the elements that tend to make a good Doctor Who story--the danger, the anachronisms, the Doctor butting heads with military types, in this case a xenophobic Earth military at war with an alien empire.
They went through a whole subplot with Evelyn over the course of several audio plays where she had a heart condition. It wasn't especially good but it's a testament to the late Maggie Stables that the character remains so effective, particularly dealing, as she must, with the notoriously mediocre Colin Baker as the Sixth Doctor. With her, he's actually not bad, and maybe it is the mark of a good actor that they can make their costars look good. Evelyn is atypical not only for Doctor Who but for Sci-Fi/Fantasy in general in that she's an older woman. She's a history professor which naturally makes her an eager time traveller and she's the perfect foil for the bully Sixth Doctor. Not only does she seem stronger and smarter than him, she's capable of expressing greater vulnerability. He really is the companion in these stories.