Might want to think twice about eating deer/elk brains. With CWD on the rise eating any kind of neural or lymphatic tissue would not be wise. Also brains have a high level of cholesterol - pork brains have the highest of any food I know.
I love eating heart, deer, elk or beef and do like beef kidneys but have never tried elk or deer. I like beef liver but my one trial of elk liver was decidedly bitter and have not tried again.