WARNING! Possible spoilers if you've not read Book 3!! I'm using spoiler tags, but there might be something that I don't think is spoiler-y that someone else will find spoiler-y so you've been warned!
If you've read/listened to any of the interviews with Caitriona Balfe that I've posted over the past few days, you learned that they have started filming episodes 6 and 7 this week. Caitriona mentioned that from this point forward, Claire and Jamie will be together again, [Spoiler (click to open)]so I'm guessing that ep. 6 is the reunion episode in the print shop. She also mentioned that she and Sam had already filmed one episode together, ep. 8, which they had to film out of sequence due to another actor's availability.
[Spoiler (click to open)]I am sort of speculating that said actor may have been Nell Hudson, and that ep. 8 would be the one where Claire finds out that Jamie had married Laoghaire during their years apart.
Also interesting to me is that if ep. 6 is the start of Jamie and Claire being back together, that means the first five episodes deal with their time apart. I was hoping that they wouldn't rush that part too much -- I didn't think 2-3 episodes would be enough to properly cover the myriad of things that happen to both of them during those 20 years apart. So I guess we're getting at least 4 episodes. I say at least 4 because Ron has already stated that they're opening with something that wasn't in the book at all -- the battle of Culloden. The question is -- will all of ep. 1 be about the battle and its immediate aftermath [Spoiler (click to open)](Jamie being "saved" by Hal and sent surreptiously away to Lallybroch, etc.).
Related to that, while there wasn't a big casting announcement from Starz, Jack Holden has been cast in the role of Hector, Lord Grey's first love who is killed at Culloden.[Spoiler (click to open)] Now, this bit isn't really even in Voyager, it's from the Lord Grey books, so it looks like they're going to expand a bit and bring in some of the Lord Grey material. Otherwise, why would you bother casting that role?