A week ago, I fond there was no air coming from the forward berth. Sent to wifi camera in and saw the duct was split halfway through. NO real access. So, I pondered and decided to go in. With no access, So I was getting anxious about this. I was going to run a 2.5” duct through the 3” one, but it is only a shortcut. So, I went in after breakfast this AM.

NOT as bad as thought! The old vent was zip tied inside. I ran a tubing (1/2” brake line) through the old vent, worked the tubing until I was able to pick up the other end that was hanging. I did this by feel. I then picked at the old vent and tore at it as it unraveled into strips. Stuck my arm in and broke the zip ties. Next, ran a fish tape through. Place the new venting over the tubing, while the vent was taped to the fish tape. Pulled vent back with fish tape while it was going through the vastness of behind the head, and reached it from other side. The new ducting was stiffer and insulated, so it did not droop in the middle. The rest is just hooking it up. I need to say my .99 stubby ratcheting Harbor freakish screwdriver saved my bacon.