I find cracking a window on the leeward side of the trailer, combined with the ceiling fan on low give us lots of fresh air. It could be different in other climates, but I find when it is raining, we are rarely in need of much venting.
2017 Escape 5.0 TA (someday soon, I hope
2015 Ford F150 Lariat 3.5L EcoBoost
2009 Escape 19 (previous)
“Most folks are about as happy as they make up their minds to be.” — Abraham Lincoln