Just letting you know I spoke to my co-GM a bit about this and he'll be posting something about this and amending what he's already put up to help accomodate to an extent.
Just wanted to let you know so you could be on the lookout for it. But the basic gist from what he told me, if the wood was already enchanted and/or has inherent magical properties, then it should be fair game for use in being used to make a wand. Then, it's just a matter of getting your core.
As for the region.... I'm actually envisioning a region bordering the areas you mentioned. So probably the southern borders of the northern highlands (or the northern borders of the southern highlands depending on how you look at it). But either way, the area will be semi populated. Though the towns won't be overly large. Just large enough. And the one that's near the castle borders the North Sea. The island (though ficticious for our purposes) is on the outskirts of the city and several miles out into the North Sea. It can be reached via boat from the city near the castle. Hope that helps. If only I could draw.... I would attempt.