If you down shift and it's a manual, you should have no problems going down. Also if you have an exhaust brake that will help alot. I have a '97 F250, manual,  7.3l with 4.10 gearing and an exhaust and never had any issues towing over the passes of the Sierra Nevadas of California going over Hwys 4, 108 and 88. I now tow with a '07, 2500, 6.7l manual Dodge with an exhaust and still have no issues. The exhaust brake will save your brakes too.

I tow all summer long up and down the tight and I mean "really" tight turns and steep up and down grades back and forth into Nevada from home and never have an issue towing. Just gotta know how to tow and use your gearing, etc.

On the up hill sections, you'll want to manually downshift the transmission to keep your engine revs up a bit and reduce the torque needed to pull the grade. With an auto transmission, this will prevent the constant gear changing and maintain a more even RPM. This will reduce your water and transmission temperatures. It would be advisable to have your transmission fluid and filter updated and possibly switched to a synthetic. This will lower your operating temps. Not running your engine flat out will lower the boost pressures, and again lower your temps.

If you have an engine braking devise, it will greatly help. If you don't, start your descents at a slow speed in a lower gear. If you allow your revs to approach the top end of your rev range, do NOT downshift; you may exceed your redline in a lower gear. Try to keep your revs low enough not to red line. Using your brakes sporadically instead of constantly, will reduce their operating temps and allow them to cool a bit between applications.

Take your time and don't even try to maintain normal traffic speeds. The safety of you and your rig, is more important than some tailgater in a hurry to no where.

Safet ... Just to clarify Gard's post.  You didn't say if your truck has an auto or manual trnsmission.  The idea is to start the downhill slow and with the truck in a lower gear.  With a manual transmission, it's difficult to shift to a lower gear when the truck is speeding downhill.  So start the descent in low gear.  The engine will keep the gain in downhill speed slow enough to allow cycles of brake on ...brake off. 

A Jake brake makes diesel engines more effective at slowing.  Even running the A/C at full blast helps engine braking.

As Gard said ... the brakes can then cool between applications.  Constantly pressing on the brakes during a long hill descent will overheat the brakes and you will have no brakes at some point.   

Those run-a-way-truck escape ramps will tear up your rig.   You really don't want to have to use it.  But they will stop a run-a-way

Not everyone is fortunate enough to have a personal translator

I took my 2005 6.0 over Wolf Creek Pass Dec or Jan.  One direction is was an empty 31 foot gooseneck with pretty good road  and one way it was fully loaded (two little cars) in a blizzard with close to  a foot of new snow already accumulated. 

I've taken the diesel loaded over many of the Colorado and New Mexico passes and haven't had a problem.  (The Wolf Creek trip was the most heavily loaded I think, and certainly the most snow.) There is something that comes on to assist slowing in the descents - and I didn't have it installed so they must come with something.  I should know what, but I don't.  I guess I'll look into it. 

If your truck is all stock in original form, it will NOT have an exhaust brake, Ford and GM never was smart enough to add one yet.  Dodge did not get smart enough until 2007.5.....

There is a way to lock and unlock the TC in the tranny, but could make your tranny over heat.  In my opinion what I would do is find someone to install a Pac Brake on the exhaust and go.

Here is a Pacbrake I found on ebay.

http://cgi.ebay.com/ebaymotors/FORD-POWERSTROKE-EXHAUST-BRAKE-NEW-PACBRAKE-/120575450419?cmd=ViewItem&pt=Motors_Car_Truck_Parts_Accessories&hash=item1c12db5d33

Also here is another deal that is chaeper that works off of the warm up valve, never used one myself but for the price, I might have to tr one.

http://cgi.ebay.com/ebaymotors/Ford-PowerStroke-7-3-Diesel-Chip-Tuner-Exhaust-Brake-/320500898344?cmd=ViewItem&pt=Motors_Car_Truck_Parts_Accessories&hash=item4a9f579a28

Does your dodge exhaust brake work clear to a stop?  The after market ones I have experience with disengage at 25 mph. You don't want your Torque Convertor to stay locked up when you are trying to stop.

The 2011 Ford and GM both offer factory exhaust brakes.

I have the BD Exhaust brake on my 2006 Ford. It works very well. I can come down 7% grades and not touch my brake pedal. The exhaust brake holds back my rig. My LQ when I had it would max out at 16,000lbs. The exhaust brake would hold that load. 

Currently my exhaust brake is disabled, there is a circuit board that I need to replace and just haven't had the extra money. My current trailer doesn't have a LQ and usually is around 10,000 to 11,000lbs.  My truck in the tow/haul mode handles that load just fine on long 7% grades.

The biggest challenge is creeping down long dirt roads. Where the I'm crawling along at 5mph and the exhaust brake has not effect.

That's interesting, I'll have to looking to that.  Most systems release the Torque convertor so they don't bog down the engine as the vehicle reaches slower speeds.

It' not a question of if the EB stays engaged. But rather how slow the Torque Converter stays locked up.

All Torque Convertors unlock and "free wheel" at some speed as you decelerate.  When the torque converters unlock, the truck goes into a Coast mode and the engine has no effect on the wheels until you try to speed up.   Otherwise you'd kill your engine at every stop sign. So I know the dodge doesn't stay locked up to complete stop. 

On normal street driving this is appropraite. But when you are in driving in very rough roads. The Torque Coverter often unlocks at speed faster than you want to crawl along.

As an old time truck driver from way back, from Colorado, with over a million and a half miles in big trucks, what he told you was not wrong, however, when you do it this way, the amount of pressure you put on the brakes is critical. With semi's and air brakes, you have an applied pressure air gauge that tells you how much pressure you are braking with. In the old days, before most of the trucks had jake brakes(engine brakes), you could come down a long grade a little bit faster by applying about 5 or 6 psi to your trailer brakes going down the hill. Not enough to overheat your brakes, but enough that you could go down the grade at maybe 20 mph instead of 15 mph. We are talking much slower speeds than what people drive now, and as I said, minimal pressure on the brakes. It's not the way I drive my pickup and trailer in the mountains now, and it's not what I would recommend. For one thing, our pickup brakes these days are disc brakes, and while they don't fade like the drum brakes do when hot, the rotors will warp and crack. The main thing in the mountains is to slow down at the top of the hill, before you start down- it takes a lot less brakes to do that than to try to slow down when you're gaining speed headed down the steep hill.

Good luck!