I've decided to first scour the trailer for a drain hose, remove the framing uptop so we can see if that end has been pushed aside or down inside the walls. And second, to check out that one hose forward of the wheels and then next drop that side of the pan and look for the hose anywhere along that side. If a hose is not found, then I will do the fish the hose down through overhead-closet and along the inside wall and out the floor, as you suggested. If it costs a little more for no water running on the sides, so be it. I'll let you know.
Thanks again for your help. I appreciate it very much. Your knowledge of Airsteams and the help and information you have offered is spread all over this forum. Your a great asset to us all.