Kris - I live in Arizona, and drive to Colorado frequently to visit family in Telluride. Let us know what kind of tow vehicle you have and we can give you some tips to be successful and not have pucker marks in the driver's seat when you get to your destination.
No matter what kind of vehicle you have, when you're going down a steep grade, the transmission shift level is your friend. Your profile says you are from Florida. On flat lands like Florida, you probably put the tow vehicle in drive and motor to your destination without giving it a second thought. When you are going down a steep grade, you can save a lot of wear and tear on your brakes by down shifting. It's not uncommon to drop all the way down to 2nd or 3rd gear depending on your transmission.
When going up hill on a steep grade, just stay in the slow lane unless you absolutely must pass. Let the engine do it's work and keep an eye on the engine and transmission (if equipped with a gage) temperatures. Here in Arizona, there are warning signs on some steep grades to turn off your air conditioner during the climb in order to keep the engine temperature in an acceptable range.
No matter how slow you think you're going, you'll likely enounter slower vehicles on steep grades. So if you're putting along at 40mph in a 65 zone, you'll likely get slowed down by a big rig hauling 40 tons of freight. Resist the urge to get right on their tail and then pull out to pass. If you get slowed down to 20-25 mph behind them, you'll likely not have the get up and go to pull out in the fast lane and pass them. Try to anticipate when you see a slow truck up ahead. When you see a significant break in traffic signal your lane change and move over to pass as quickly as possible. Sometimes your best intentions can't be met, and you'll get stuck behind a slower vehicle. If that's the case, just be patient and sooner or later, there will be a very large break in traffic and you can take the time to pass, or the climb will conclude and you'll both start moving faster.