First off, stop thinking so much about brakes and think more towards downshifting to 2nd and using an exhaust brake. Maybe the 150 doesn't come with one as the new 350 I drove does. But on my older 350 I've added a Pacbrake and seldom need to apply the brakes (make sure overdrive is off). If the grade requires braking I'll downshift to 2nd. We live at 9000' feet, and DW and I both avoid over-braking. Before we were experienced we (I) overheated the brakes coming off of Mosquito Pass on the Leadville side in our old Bronco. Luckily, they held until I got into town. What a surprise when I blew through a stop sign without even slowing. You don't want that to happen with or without a trailer pushing you. And it's a great aid even on level roads when that yellow light pops up or some clown cuts in front of you in traffic.