How "Sherwoody" do you want this thing to be?
The closer you stick to the legends, the more options you'll have to cut back- many base classes and PrCls simply wouldn't fit thematically. Since the legends weren't to rich in magic, for that matter, you might want to take a look at a lower-magic D20 variant like Iron Heroes.
Otherwise, you might want to eliminate the full casters, or cut their spell progression or access down. If you go the former route, you might use a modified Bard for your main casters- including the Divine Bard variant from Unearthed Arcana.
There used to be a thread about a Monk class based on a European model, like Cistercians, Brother Cadfael or Umberto Eco's Name of the Rose, but I believe it was lost in the last crash- I can't find it, anyways.