All of the posts on this subject have been very helpful.
Here is the unit I bought for $288.
http://www.amazon.com/gp/product/B006YG ... UTF8&psc=1
I picked this unit because it fits between the seats of my Ford 250 which is the only place it could be, given my configuration. So far it has been very effective although we have not had any 90+ days, yet but I am optimistic.
I looked into venting it through the floor but not feasible because of heat shields, drive shaft tunnel, cables, brake lines, etc. where it would need to go. I will look into that again for next season. As I needed something immediately, I used a piece of acrylic and some velcro to affix it to the outside of the passenger window. It works fine for now. Cutting an opening in the middle of the acrylic was a bit tricky. I used a spiral bit on a RotoZip router but it was too course and it left a ragged edge. It works but I am used to producing better than that.
So I will field test it this summer and make any improvements this winter. It is much quieter than the Danhard both inside and out. Plus it is cheaper by at least $2000! I wish Sportsmobile had spent their energies developing and building in a unit like this instead of offering the noisy Starcool and then the equally noisy Danhard.