Grind the fat and venison together using a fairly small die (4.5 mm). Transfer the mixture to the bowl of a stand mixer.
Mix together the contents of the packet of LEM Backwoods Summer Sausage Seasoning & Cure with the recommended amount of water. Whisk to dissolve as much as possible. Pour the mixture over the ground meat and fat.
Using the paddle attachment, beat the mixture on medium for 30-60 seconds until the mixture is tacky and holds together. Quickly mix in the high temp cheeses until well distributedTransfer to the refrigerator to chill.
Place two LEM 2 1/2" X 20" Fibrous Casings in warm water, and soak for at least 30 minutes.
Transfer the sausage mixture to your sausage stuffer, fitted with a wide stuffing tube. Remove the casings from the water, thread onto the stuffing tube. Fill the casing with the sausage, twist the end of the casing and tie off with butcher’s twine. Repeat with the second casing.
Place the sausages in the refrigerator on a wire rack (cooling rack). Let sit over night.
The next day, preheat your Yoder Smokers YS640 pellet grill to 200ºF. Place the summer sausages on the second shelf of the cooker and smoke until the internal temperature reaches 160ºF. Remove from the grill and place in the refrigerator to chill. Remove casing and slice to serve.