I have had a tough elk or two as well. One was a spike... if you can belive that. He hung in just above freezing weather for a week too...
I have cooked it many ways. One of the best is to slow roast it in a moist environment.
Pot roast will turn the toughest meat into delicious edible pieces.
Crock pot it with two cans of chiles and a can of french onion soup and a little chipolte sauce, patatoes carots and oakra... One of my favorites.
Maranade in Mcormicks Hawiaiian sauce and add olive oil, garlic, then sear it on the BBQ, rap in tin foil, add some of the marinade and top it off with blue cheese and cream cheese roast it untill it starts to fall apart.
You can boil the steaks for about an hour or untill they start to fall apart, make them into BBQ sandwhiches, or another one of my favorites, Enchaladas... If its tough, just cook it until it falls apart...
Sometimes meat is tough if you cook it too fast too hot. Try cooking it on the BBQ on low for about 20min or untill meadium/medium well. Slow cooking will sometimes make tough meat edible, others it won't help.
good luck
Ivan