I'm currently running ToEE, and that hasn't required too much in the way of conversion. Mostly magic items and finding equivalent creatures. Might be more work than you're interested in, however.
White Plume Mountain should be easy, especially since the three named weapons are in the DMG (which would have been the hardest to convert).
Keep on the Borderlands was redone during the playtest, so it would be a super easy conversion as well.
Not classics (but faves of mine), I did the Sentinel and the Gauntlet during the playtest, and it required almost no work to convert (I substituted the Kobold stats for the Xvarts).