Kathy:
On our 6 month trip to the east coast last year, we made it to Quebec before the heat got to us. We stopped at a Walmart and picked up a portable AC. I knew we were going to be purchasing one at some point in our trip, so I put a "door" in the side of our CT for the vent before we left.
I had done some research and found that there really wasn't much difference between a single hose unit and a 2 hose unit, so I opted for a single 5" outlet - one less hole in the side of the trailer to leak!

We carry the AC in our clothes (hanging) closet at the front of the trailer. We just pull it out, attach the hose, point it to the rear and turn it on. BTW, I installed 1/2 of the window mounting bracket so the hose attaches securely. The pink "plug" is my winter cover.

On the outside, I got tired of having to open the door, so I installed a louvred vent. We're still waiting for Spring here on Vancouver Island so I haven't had a chance to fire up the AC but with all the rain we've had recently, we haven't had any leaks.

We have not had any problems with our portable unit. And you are right, the air leaving the hose is quite strong - that's why I used the window bracket so I can attach the hose securely. My early attempts were the same as yours - too much "wind", just blew the hose right off.
As far as our unit is concerned, there is a noticeable difference in temperature in the CT. In the living room at the rear, it is nice and cool. At the front, on the "other" side of the AC, it is noticeably warmer. All in all, we are glad we've got the AC. We lived very comfortably through 101F temps on the east coast of the US last summer.
Hope this helps.