Beachgirl,
From what I've been told by others here and on SOITC's forums, I would suggest the two 15K air conditioners, especially since you say you will be more in the warm country than cold.
While Jo and I think the Lasko is stylish looking, it is a ceramic heater. I don't know if there is a fan in the system. I do know it oscillates back and forth, so I would presume there is a fan. On one of the forums that I frequent, there has been a long running discussion of the Vornado brand electric heaters. Here is a link to that discussion. It runs something like 25 pages.
http://www.myrvtalk.com/interior/307...o-heaters.html
As for the hitch, we have a Reese 20 or 22K fifth wheel in the pickup and the Trail-aire Pinbox with tri-glide on the MS. We pulled it to Carthage, MO back in October to a mini-rally and other than a couple of times on bridges, there was absolutely no chucking. I should also add that most of that driving was on Oklahoma roads. (Ask any RV'er about Oklahoma roads.)
We also have the Trail-Aire suspension on the MS as well. When ordering the MS, we didn't know about the tri-glide on the pin box, but ours came with it, so I would guess that it is standard with the Trail-Aire pin box. But, check with your dealer to see if it is necessary to also get the Trail-Aire suspension. By the way, we really like the system, even for the little time we've pulled the MS.
Terry