Since you're already a lightweight backpacker you have it easy.  The only challenge for us backpackers to bike tour is how to haul our loads on the bike (or trailer) and not have the load carrier system be too heavy.  Just as backpackers need to watch the weight of their backpacks we need to care about what our hauling set up weighs.  The weight of your trailer may very well exceed the weight of your gear.  Not a very efficient  way to go after you've put all that effort into lightening up your gear.  For road and light trail touring some of us use just a rear rack and a couple of lightweight suffsacks tied to the rack.  Panniers can be heavy too, there are some that are lighter than others, if you want to go that route.  By looking through some of the old posts on this list you can get a pretty good idea of ways to lighten up the way you haul your gear.  A trailer is a wonderful thing for day to day shopping and leaving the car at home.  I suppose if one wanted to camp heavy they also might be nice.  But I think you'll find for ultralight bike touring it isn't the most efficient option.   

Gary Blakley