I have been eyeing one up for my alaskan, but I wanted to know from a user how big of a gap there is between the side of a vehicle?? Ie how much rain would get in between??
There's no gap between the opening side of the case and the awning fabric, so no water gets in on the business side.
Whether water gets into a gap between the back edge of the case and your truck/camper is entirely a matter of the mounting. My Foxwing case is mounted solid and flush against the thick side wall of the camper, so rain water can't get through. But if you mount it any other way, you're likely to have a gap and some rain will still flow down the side of the truck. That said, whatever water hits the Foxwing goes away from the truck, so the awning doesn't add any more water.
The Foxwing is outstanding in the right circumstances. The three cautions are that it takes two people to deploy in a wind, you need quite a bit of open space around the truck to extend it, and you need to figure out a good mounting system before committing to it. If you can get past these issues, it's great.