Sorry it took a while to get these, had a few things going on this evening. I will admit I am not an expert, but here are the steps and some pictures of what I did. The difference after I was done was night and day (made my wife and kids very happy!)
Here are some of the pictures that I captured (going to have to split this into a couple of posts):
First start off with the air vent:
You need to remove the cover:
Once you have the cover off you will most likely see some tape already:
You will actually need to feel around the inside of the vent for small gaps or holes where taping was missed. When you are done you should not have any gaps, took me quite a bit of tape as there were some big holes.
To put the vents back on, just do the reverse of taking them off, the louvers in the vents can be a bit of a pain at times and I had a couple that would actually continually shut from the force of the air. I just put some of that tacky putty used for handing my kids artwork on the walls in between the ends of the louvers and all is well!
Repeat for each air vent in your camper.