There's a couple of old 1e modules - C4 and C5 - that are actually 8 little adventures (4 in C4, 4 in C5) linked together almost like a mini AP. There's a decidedly Celtic feel to a couple of the parts and it wouldn't take much work to tweak the rest to suit.
The only problem is, with one exception* the adventures themselves are IMO awful. They're the only modules I've ever actually stopped the game partway through and apologized to the players for running; my only defense was and still is that they read considerably better than they play. But, if you approach with caution and be ready to do some tweaking - or just use them as idea fodder - you might be able to squeeze someting out of these.
* - the exception is the bit involving Krell the robber baron (you'll see this if you get the modules), which worked out really well when I ran it.