I'm excited to try the new Pork Shank at Gaston's Tavern! In all the parks, the fruit stands have fruit, hummus, and carrots with ranch--might work for you, might not.
Other good bets--
in MK: Columbia Harbor House has a salmon platter with broccoli and you can order extra broccoli. Cosmic Ray's, as stated, is good.
In Epcot--so easy! A lot of good CS options. Sunshine Seasons & Morocco (schwarma!!) are favorites.
In DHS--I know they have turkey legs.
In AK--flame Tree BBQ, but ditch the sauce & beans.
Also check out any Paleo/Primal threads for more ideas.