IUD strings lower than usual? 6 months post insertion. No cramping/pain but some light spotting. Can't see DR yet due to a blizzard. Any advice?

Continue to monitor. I don't think you have to worry regarding string length. Unless it is protruding out of the vagina. Light spotting is common with IUD's just continue to monitor. Just in case if you are concerned have your partner continue to wear protection for both STD's and Birth Control. But I would always recommend protection against STD's regardless of the IUD, because IUDs don't protect against STDs.