Don't know where you are on this.
I'm third generation with aero, all-aluminum travel trailers. I've been pulling them forty-five years. Noted above that there is no substitute for right design & construction is correct. This trailer-type is essentially of indefinite lifespan. Call it 250k or 25-years before a rebuild.
And comparing these to a box trailer is way off. There's not a decent comparison.
First, a ten year old isn't old (Airstream only survivor from the Golden Age, so we will use them as stand-in for AVION, SILVER STREAK, and STREAMLINE). A ten year old AS is a better trailer than anything at the box trailer lot. By construction only.
The important difference is design. Fully aero means good entry & exit (horsepower demand), but what really matters is crosswind stability. This is fully sealed underside and surfaces are fully-radiused into each other. Then low ground clearance. And fully independent suspension.
Loss-of-control accidents are not problems in skill (that's a laughable defense) but go directly to design. On a square box the winds pile up and increase in force the length of the trailer. This is what you'll see in wreck videos. The tail gets sideways (airborne) first.
High ground clearance only worsens this. Slide-outs have caused TTs to have a floor nearly four feet off the ground. And the crudity of leaf sprung suspension is reprehensible. LS itself isn't bad, but it's design must be right. On conventional TTs it couldn't be worse.
So you've got the wind pushing like crazy, and the barely four inches of suspension travel can't compensate.
On an AS the wind isn't trapped. It flows over and exerts a pull. A much gentler force. And can't build a wedge underneath as the torsion axles help compensate.
The AS only needs (what you should add) anti-lock disc brakes. That and the state of the art brake controller from TUSON CORP.
A box trailer might last 75k miles. For a high annual miles user. Service life will be less than ten years (break out the moisture meter: water WILL have invaded). IOW, it won't last the life of the finance note. This is why you see RVers trade so often. It's a need, not a want.
My folks bought their Silver Streak when I was in high school. Sold it 27-years later when my son had started college. (And that owner still has it on the road). Dad replaced the main awning near the end, and there were some other repairs along the way. Ever walk into a place at age 45 where things are the same as when you were 18?
That trailer crossed the continent numerous times. My grandparents Streamline added all of Lower Canada and nearly all of Mexico to that.
Of course we used cars. Still the better tow vehicle over any pickup. The name of the game is
stability which pickups don't have. They're the worst thing on the road as far as that goes.
An Airstream has greater stability than any pickup. And continues higher in speed behind a better TV where a pickup has already rolled.
The pickup will be the SOURCE of the accident versus an AS in tow.
4WD only makes it worse. Dead steering. The trailer will (does) get past the point of control before it's felt at the steering wheel. Buh-bye.
Those unibody cars we had easily lasted 12-years or 200k. And those trailers were each in excess of 7,000-lbs. 1,100-lb tongue weight. Which is no challenge if one understands how a weight-distribution hitch works. (97% don't. You won't find it on Stupid Tube). Low center of gravity plus better suspension & steering sophistication are what's wanted.
The hitch & it's rigging are just as important as the choice of the two vehicles. But a pickup truck tow vehicle is the weak link.
That's best addressed with trailer disc brakes, controller, and a Hensley-patent hitch (either branded Hensley or Pro Pride). The trailer will not come out of alignment with the tow vehicle. No sway is a guarantee. No other hitch is on its class.
The usual dummies (who've never used one) will crybaby about money. Not understanding "what is value?"
Suffice it to say there's not a pickup out there doesn't need it. Big bandaids right off the showroom floor.
Take your current pickup to the closest truckstop that has a CAT Scale (get phone app; and see video). The only items in the truck are what you will leave in it till the day it's sold. Top off the fuel tank.
The single scale pass with the driver only (corrected TARE weight) is the lightest the truck will ever be. With the scale ticket, compare the Steer abc Drive Axle values to the door sticker showing axle/tire/wheel limits. "Payload" and "Towing Capacity" haven't any meaning. Here, we are looking at legal limits (I'm also a professional driver).
The difference from scale ticket to door sticker is how one adjusts a WD hitch. The old rule of thumb was One Third Distribution: Steer, Drive & Trailer. A 1k TW was thus 330-lbs to each axle. Now, it wasn't ever perfectly so, but it was the guideline. And still is.
There's a single key: Steer Axle Weight.
Takes three scale crossings.
Loaded & hitched for camping. Full fresh water & propane in trailer plus all passengers aboard.
1). First Pass: hitched with WD tensioned.
2). Second Pass: same as above but with WD slack.
3). Drop trailer and return for solo weighing.
Get all three printouts from fuel desk. $11 for first and each reweigh $2.
These are also guides to correct tire pressure.
Now, that was actually the fine tune stage. Where One & Three have the same Steer Axle value.
The start is at home with a rough in. The trailer is dead-level with a carpenters level across the door threshold. There's no allowable deviation from this.
The guide (best one) is from the Can Am RV webblog: Hitch Hints: "Setting your Torsion Bars".
Etc
Etc
How much can I tow (wrong question).
How well you set the hitch rigging is everything.
Obviously there's a lot more than this.
Just remember that there is no substitute for design, nor for getting the equally important rigging correct.
The last laugh (at conventional nonsense), "oh, a fifth wheel is more stable than a bumper pull". Really? There's not a fifth wheel out there that won't roll over at speeds where I can make emergency double lane changes with my 35' in tow. And continue on. In winds that force them to stop for the day.
Take your time.
www.airforums.com is a big site. Use Google searches vs website. Lots of folks with older trailers. Mine will turn thirty this next year. Not old compared to some.
And, while it's true I had the advantage of a lifetimes experience with these, I bought both vehicles in used condition for just a scratch under $30k combined. Ironically, the TT would sell for much more than I paid, and the TV has had but $4k of depreciation in those eleven years.
If you've room to park it at home, you're set. Under hard cover is best.
Good luck.
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