I've been going over the official announcements for the Dwarrowdelf cycle, because I'm full of an almost unbearable excitement for this, and have been turning over the idea that we may not have seen the last of the core set encounter cards. At first, when Khazad-dum was announced as being a required purchase for this cycle, I presumed that it would hold all the encounter sets needed, and no longer would we be plagued by such things as The Brown Lands, Ungoliant's Spawn, etc etc. But last night, I read this:

http://www.fantasyflightgames.com/edge_news.asp?eidn=2715

More specifically, the first paragraph of Lucas Litzsinger's description:
The Dwarrowdelf cycle allows players to travel along the Misty Mountains as well as delve deep into Moria. While the cycle’s narrative arc stands apart from the one in the Khazad-dûm box, the two are closely knit thematically. Players want new scenarios to feel as fresh as possible, which is why Khazad-dûm has six different encounter sets for use in the Dwarrowdelf cycle (whereas the Core Set has four). This allows us to better differentiate the areas players will be exploring and is why Khazad-dûm is a required purchase for anyone who wants to play the Dwarrowdelf scenarios.

For months now I've just assumed he was saying Khazad-dum has six encounter sets for its subsequent adventure pack cycle, whereas the core set only had four for its cycle. But over the weekend I've finally come to realise that isn't right, because there are five encounter sets from the core set that are used throughout the Mirkwood cycle. That, and the fact that the encounter sets in Khazad-dum, except for maybe the Misty Mountains set (the one that isn't used in any of the scenarios in the expansion, I think that's what the set is called, anyway) just don't seem to look right for stuff you'd encounter up a snowy mountain. There are one or two that could, at a push, be included, but largely the encounters of Khazad-dum are full of interior-style locations.

So is it just me? Or do you think we'll be seeing that **** Hill Troll halfway up Caradhras?

yes, that is what it means (kind of).. but remember that there will be a unique encounter set for each AP as well, and there is nothing to stop them adding some of the packs form Core as well.. Also the Darowdelf cycle starts in the mountains and then goes down to the gates of Moria, I mean pack 4 or something out of 6 is the Watcher in the Water... . . so pretty sure we will be close or in the mines by the end of it

well themeatically it wouldnt be so far out to see trolls and goblin snipers in the mountains in the first two packs- in the low lands near rivendell i.e. the trollshaws- it would be pretty much spot on, so i wouldnt have a problem with seeing some old friends again in the earlier dwarrodelf packs

It also makes sense if they want to keep selling Core Sets.