One of the recent additions to the Xtracycle have been the purchase of WideLoaders. The WideLoaders are the horizontal racks that shoot out to the side of the Xtracycle FreeRadical (where the weed trimmer is sitting). Their purpose is to hold a wider load and support cargo with more rigidity than the FreeRadical bags themselves.
In the original purchase of the Xtracycle, I didn't think I would really need haul anything with that much bulk. And to be honest, I didn't want to incur the extra cost. But after a few weeks of using my bike as a truck, I was realizing that this may be something I would use. I hated getting to scenarios where I could use the Xtra if I had a set of WideLoaders.
I began to hunt for junk in my garage to dump off on Craigslist. Eventually, I remembered I had an old G4 PowerBook in my closet that hadn't been powered on in over two years. Jackpot. Fast forward through about 93 spam emails for Craigslist and here we are, carrying a weed trimmer to work.
These really have been a great help with cargo. If you're considering something like the FreeRadical, I will warn you. You may be unsatisfied without the WideLoaders. The Longtail kit does wonders. It completely changes your lifestyle on a bike. But you will probably find yourself in the same spot I did. You could do more with this tool added on.
Get out there.