My Outback is 35 1/2 feet long from bumper to hitch. Add another couple feet for my cargo carrier on my bumper and that put my Outback at about 38 feet. Add the truck length and that puts my total length about 59 ish feet for truck and trailer.
I've never had problems towing, parking, getting fuel, campsites, sway, backing up, getting into dump stations, restaurants, motels (when we've used them in the winter traveling in snow country), or anywhere.
No granted, we selectively choose our camp sites, always ensure the space is long enough and wide enough (we have slides on both sides) and make the determination before booking a site if we can camp with slides in or slides out. (width is just as important as length).
We went from a pop-up (that had the same wheel base as my 5x10 utility trailer). Towed it with a Mine Van and later a suburban. It was awful backing up (short wheel bases is always harder to maneuver).
Next camper was an 18 foot travel trailer. Initially towed with the Suburban and later a gas diesel. It was somewhat easier to back up, but because of the long wheel base of the truck, backing was still a bit of a challenge.
Then went to a 31 foot Travel trailer, and continued owning 3500 dualy's Crew Cab long bed trucks. And back-up was never a problem.
Now, have a 35 1/2 foot trailer, 3500 duly, and have found absolutely not issues back-up. It's actually much, much, much easier than that pup-up ever was.
It takes extra planning and a little fort-thought when owning a longer trailer. THAT is the difference between owning a longer trailer and a shorter one. You just have to plan ahead a little more careful.
You will not be able to get into every camp site, you will not be able to park a 31 foot trailer in a tent camp site, you will not be able to go through a McDonald's drive through, you will have to park out a away in a grocery store parking lot, you will have to do a quick evaluation of every fuel station you encounter spot your exit strategy, you do have wait sometimes for traffic to clear a tight intersection so you can make that right hand turn. You do have to have a bit more patients, and always have to be aware of your length behind you, and how much the trailer tail sways when making a turn.
But, after a VERY short while of towing, all of this becomes second nature to you, and you are not consciously thinking about all these things until someone asks a question. Then you realize how much you've changed your outlook subconsciously.
Sway? If you have the right tow vehicle, with the right hitch set-up, sway control, and weight distribution, you should never experience sway.
Towing? My current Outback tows so comfortable, I often forget it's back there until I look in the mirror and approach a stop or begin a turn. When everything is hitched correct, a longer trailer tows extremely comfortable.
There has been a lot of debate on these forums about speed and towing. One thing you should always do, regardless of what you drive or what you tow, always tow and drive safe. It's not about speed, it about safety and arriving safely and returning home safely. Factor that into EVERY trip you make, and you'll never have any issues. Safety on the road supersedes everything.
One more word about 'size'. Think of it this way? If the semi-trucks can do it, why can't you?
(And I've never had problems navigating most fuel stations.. I do not use truck stops unless there is absolutely no other place that sells diesel. I've been able to encounter gas stations with no problems. Yes, it take a little fort-thought, and sometimes there is one that just can't be navigated. But 1000 feet up the road and the next one can be!