I just finished a tour in colorado, San Juan MOuntains. Slumgullion pass coming from the north is STEEP.
I toured with a trek 520 pulling an ''extrawheel' trailer. The total load of trailer and gear was 40 pounds, and I had a handlebar bag - ten more pounds including the bag. add another 8 pounds or so of water for a total load weight of 68 pounds. the trek weighs about 28 pounds with the fenders and rear rack.
My first attempt using a trailer, and I'll do it again. The trailer is a marvel of simplicity, carries the load low, so the heavy items are below the trailer's axle. I usually could not tell the trailer was even there, even downhill. Well not quite: down hill going very fast, (35-40 MPH) a slight movement of your body will cause a reaction in the trailer, so sit still. I was never very comfortable travelling over 25 MPH downhill with this bike loaded with 4 panniers.
the BEST thing was that it balances the bike so well that standing while pedaling is a breeze. I was not very comfortable doing that with the panniers either since the bike gets rather wobbly as the rear panniers react to the motion of pedaling while standing.
like other revierers, I was suspicious of the yoke that attaches the trailer to the supplied rear skewer, but it function flawlessly. It just looks 'too simple' to work. this trailer is really an engineering marvel, IMHO.
it worked so well that I'd like use my tricross (18 pounds) to pull it rather than my touring bike (probably 28 pounds including back rack). my tricross (campact double) is geared too highly though. I still needed the 17.5 gear inch granny on the trek to get up slumgullion pass, which climbs probably 2500 feet in 6 miles or so, and i dont think taking ten pounds off the bike would have helped much.