We line a loaf pan with non-stick aluminum foil to put the meatloaf mixture into to make it easier to remove after the loaf has been formed. After that, we flip the loaf pan onto an oven rack, remove the foil, and then place the rack directly on the bottom of the grill grates. Make sure to spray the oven rack with some Pam before putting the meatloaf on it. If you put the meatloaf directly on the grill grates, some of it may fall through, not to mention, it's hard to get the meatloaf easily off the grates. Once done, pick up the oven rack with the meatloaf on it, take it inside, use a couple of spatulas to remove the meatloaf, and enjoy. Racks similar to what we use can be found on Amazon, but this is similar to what ours look like:
https://www.amazon.com/Checkered-Chef-Cooling-Racks-Baking/dp/B06X9KLW1P/ref=sr_1_5? Being checkered keeps the meat from falling through, but allows the grease to completely drain away.
Check the Traeger recipes for times and temps. We personally avoid trying to smoke the meatloaf at low temps first, and instead, cook it at 250° until about 170° IT using a ThermaPen. I use a smoke tube, so it has a slight smokey flavor. You may need to cook yours a bit more or less depending on the mixture and size. Ours takes appox. 2 hours of cooking time for 1.5 lbs. of ground beef. Of course, higher temps will get you done sooner.
BTW, that Pastrami looks delicious!!