AGFazio makes a good point, it was going to be my contribution to this thread but I wasn't quick enough. Unless you have a door the slides open (to the left or right) you aren't going to get all 14' out of the opening. I don't have a garage for my RV (yet), but my "regular" garage at home is a 7' opening, but I can only get a vehicle inside if the vehicle is less then 6'7" because of the way the tracks/door is positioned when open. If that makes sense?
2015 Rockwood Mini Lite 2504S
2015 Ford F150 Ecoboost