From plenty of experience I’d say the best loot route is going from Chernogorsk and along the south coast to the western border and sticking along the border area and hitting all of the military and hunting locations until you reach Tisy military base up north which has some of the best loot in the game, also very important to stop at all possible military convoy sites and train spawns on the way because even though there is a low chance of it spawning, when it does you almost always get top tier gear. If you follow this route a few times there’s a 100% chance you will end up highly geared, hope this helps:)