We bought the Patty O' Room for our 5th wheel, it attaches to the power awning and we had the dealer install it for us (It is covered by the warranty on the trailer because the dealer installed it). They used the twistlock attachment and put silicon under each twistlock. They also recommended the heavy duty velcro where necessary.
We had an add-a-room on our previous tent trailer, and it used velcro exclusively. I had to replace the velcro every 3rd year to keep it fresh, and to replace the parts which were under the trailer and prone to road debris. The Patty O' Room comes in 3', 6' and 8' panels and also has the ability to use a screen door instead of a zipper. We loved the add-a-room on our tent trailer, and insisted on one for our 5th. With the awning, ours will be 8' wide by 20' long.
2009 GMC Sierra SLT Crew Cab 4x4 Diesel
2010 Rockwood 8280SS
Camping 2012: 40 nights