Dr Who Earth Story - Simply put, both the stories happen on Earth, and have some links to famous time periods within history, i.e the wild west and the civil war.
As far as I'm aware the Gunslingers has never been released before, not even on the old VHS. So for me, a fan of the show who isn't old enough to remember the original airing of the story, this is quite exciting. The TARDIS and crew land in Tombstone, one bad sweet later the Doctor needs to visit a Dentist and meets Doc Holliday, from there the adventure ensures.
The Awakening, is in fact the last of the Peter Davison Stories to be released, a 2 part adventure which is based around an evil force manipulating the local civil war reenactment. Although not as good as some of the other stories in his final session (Androzani, Ressurection), The Awakening is a nice little romp in the country, and it will complete the Davison era.
The usual commentaries are available.