A friend of mine and his brother trailered their bikes out to meet two of us riding west in 2008 and left their Dodge dually and 24' trailer at the KOA campground in Limon, Co. just east of Denver. We left it there behind the owner's house while we rode for 16 days and then the 4 of us loaded all the bikes on the trailer and came back to Ga. They were very nice, cheap, and guarded 24/7. They have an overflow lot at the back of their office/house and 2 other riding groups had done the same thing. Their info is on the KOA website...
http://www.koa.com/where/co/06142/I hope you enjoy it out there as much as we did. We rode in every state west of Kansas and went into Canada north of Washington to Calgary, then came back down into Montana.