Light Touring w/ Carbon Fiber bike
 

I have a specialized roubaix and i want to do some light touring in the san juans this summer.

Is the best thing for handling/comfort to just buy a trailer? or should i look at building a cheap steel touring bike?

I built an aluminum touring bike based on the Nashbar frame. Didn't want to risk having my expensive Cervelo RS stolen and I didn't want to pull a trailer. I splurged on wheels and a bought a trekking crank, but just about everything else came out of the parts bin...

Depends on how much stuff you plan to carry.

If light means pulling a trailer, what's heavy touring?
The bulk of my cargo while light touring is a pair of flip flops, a wind jacket, and half a toothbrush. Saddle-bag stuff.

Curious.... The Islands in Puerto Rico or the Islands in Washington State?

IMHO, I'd rather spend the money on a bike suited for touring than spend the money to replace a bike that was not meant for touring should you damage it on your ride. The San Juan's are a nice place to ride so I'm sure the Roubaix would make it but we all know that things happen and for me personally, I'd rather go being armed for whatever than trying to avoid every possible mishap. I rode around the San Juan Islands a couple of years ago, they are beautiful, ENJOY!

I only suggested a trailer because i knew what a crime it would be to try and put 20 lbs of gear on my bike.

San Juans in washington state. I go every year.

i'm getting ready to sell my old ride to buy a new commuter/beater/rain bike since my main bike won't be left all over the city.

I really want a LHT but i'm a student and i just dropped 1.5k on my Rubaix so there is no WAY i can justify spending 1k on a LHT.

Even though I'm not in the market for a new bike, I always keep my eye on Craigslist. By typing in Vintage to my search under bikes, I often find bikes with steel frames that can be had for sub $200 and with a few modifications could make great touring bikes. I recently saw an 80's Specialized Stump Jumper which is a rigid frame MTB w/ triple crankset, in nice condition, for $145.00. If I were in the market, that would have been gone.

you probably know this already, but don't try to use clamps to attach a rack to a carbon frame.

I did some light weight touring with a full carbon frame (well aluminum post). Assuming you have or are willing to get an aluminum post you could consider getting a Carradace Nelson Long Flap and Bagman rack from Peter White, a Jandd frame bag, large bento box, and small handlebar bag. If you go this route you will have to be very diligent with gear selection and stick with ultra-light backpacking equipment, but that is a whole other thread (search on this board for more on ultra-light touring).

http://www.peterwhitecycles.com/imag...Packs/NLF1.jpg

http://www.peterwhitecycles.com/imag...acks/BAGQR.jpg

http://www.jandd.com/ProdImages/Bicy...k/FramePac.jpg

a frame pack might be the ticket. It's a bigger, custom version of the bag mtbmaven posted. combine it with a messenger bag or backpack for the lighter bulky stuff.

http://cache.backpackinglight.com/ba...4344_17530.jpg

Following up on rench123's idea. Check with Carousel Design Works and Epic Designs for custom bags. Jeff at Carousel built a frame bag and seat bag for my MTB. Amazing craftsmanship.
http://i25.tinypic.com/5n5h51.jpg

http://i26.tinypic.com/15hifc5.jpg

http://otbmbc.smugmug.com/photos/255824878_wV7ci-M.jpg

http://otbmbc.smugmug.com/photos/255888301_izZYJ-M.jpg

The Roubaix will likely be OK for a short road tour (1-2 weeks). Get wide and robust tires; make sure your saddle can handle high mileage; maybe raise the bars for the tour. If you want to carry a lot of crap, use a trailer.

FWIW I wouldn't go the used / beater route unless you've got a ton of appropriate parts and/or are good at bike mechanics -- or to be precise, I wouldn't regard it as a real way to save money. Buying a used bike can easily turn into a money pit.