Hello KBarley -
An option you may want to consider. I recently bought two Adventures and for a number of reasons, a trailer was our preferred means of transporting them. Although I serously considered the options listed above, I ended up buying a Versasport utility trailer made by Snowbear, adding a Thule system with the Hull-a-ports. Although the relative cost of this approach is favorable, one of the big advantages over the others trailer is the simplicity of hauling all of the supporting Mirage gear (drive system, sails, etc.), with plenty of room for some camping gear. I have had it for about a month and so far, I am very happy with it.
Please note, there are two similar trailers, both made by Snowbear.
1) The Versasport by Snowbear, $649 at Costco (in Northern California). Unfortunately, I cannot find it on the web. The primary advantage it has over the regular Snowbear are tubular rails on the side that work perfectly with the Thule system. The model below does not have these rails. Also, this model has two tongue settings, one being long enough for the Adventures. I'm not sure about the regular Snowbear. To find a dealer or get info about this model, you may need to contact Snowbear.
2) The second model that is very similar is the regular Snowbear 8000 http://www.snowbear.com/html/8000.html
. Locally, they are available at Home Depot for $699. Though it may not work as well with the Thule system, you may be able to come up with another system. Worst case, add padding to the "tailgates" and lash them down.
If you have any questions, please don't hesitate to email me or post a reply. If you decide to pursue the Versasport option with a Thule sysem, there are a couple of important adjustments I needed to make to my installation.