Papain meat tenderizer is your friend for really tough meat. It comes from papaya, and breaks down the fibrous protien in meats. Get a meat injector, chose an injectable marinade that piques your fancy, add the papain powder but be sure you follow the directions and only add the right amount per pound or you'll get mush with a crispy shell.
Best way .. Fry it like fried chicken with your favorite fried chicken recipe. ... But soak it overnight in a buttermilk marinade to tenderize it.
People have used milk or buttermilk forever to tendrize and buttermilk works well if your going to fry. It's lightly acid and thick so the flour/cornmeal spice blend sticks well.
Cut the gator in small pieces and refrigerate in lightly salted buttermilk marinade spiced to taste. Black pepper, fresh ground peppercorns, or crushed red pepper? Garlic? Cayenne? The Kentucky Fried recipe guesses off the internet? Too many different tastes in spices so follow your own preferences.
Have a pan of flour and a pan of lightly peppered cornmeal ready. Maybe a little crushed red pepper in the cornmeal or a little of Zatarain's rub if you like it hot or cajun, but not too much 'cause some folk don't like spicy or hot at all.
Quickly, drop thouroughly wetted marinated gator meat in the flour (don't roll as you get too much of a flour paste, lift flip and drop other side, Now you can roll it in the spicy cornmeal which will stick to the flour paste well and give you more of a spicy cracklin kind of crispy as you fry it up.