Defrost pie crust if frozen, allowing it to come to room temperature.
Preheat your Traeger Grill to 375*.
Wash and cut the apples into thin slices, leaving the skins intact.
Toss the apple slices in a bowl with 1/4 each of the brown sugar, toffee bits, flour and cinnamon.
Stir well to coat.
Roll out the pie crust into a pie plate, pinching the edge if desired.
Pour the prepared apple slices into the pie plate, pressing down to fill the crust and make the top even.
Drizzle the apples with caramel sauce.
In a small bowl, combine the remaining brown sugar, flour, toffee and cinnamon with the rolled oats and pecan pieces.
Stir to combine.
Add the butter, cut into pats, to the bowl of ingredients.
Using a pastry cutter or your hands, combine the butter with the dry ingredients until combined.
Pour the prepared crumb topping on the apples and press down to adhere the topping.
Place the pie in the hot Traeger and close the lid.
Bake for about 50 minutes before checking.
Turn the pie 90* if necessary to allow even browning.
Continue baking the pie another 10-20 minutes until the filling is bubbly and the crumb topping is golden brown.
Carefully remove the pie from the grill and allow to cool for at least 15 minutes before slicing and serving.
Serve your toffee crumb apple pie with vanilla ice cream or whipped cream, if desired.