Loading in trailer without vehicle attached

I am starting a new guy and teaching him to load on a trailer. My way of doing this is each day he loads a couple of times, does it correctly and then he is put back in the field. This only takes about 10 minutes but the hardest part is constantly hooking up the trailer to the truck. Aligning the hitch.
I decided to forgo the truck and just rig the trailer so I don't need the truck.
I used 4 jack stands, the type most husbands have in their shop or 4 blocks of wood would work just as well.
I park the trailer on the grass so the wheels won't roll, drop the tongue down a bit by cranking the handle and then place 2 stands/blocks under the back of the trailer , at the corners. I then crank the tongue up ontil the rear blocks are loaded.
I then put 2 blocks under the front corners of the railer, against the frame and near the front at the widest point.
I then lower the tongue again until these blocks are also loaded.
I then just snug the front jack until it too still retains load.
I now have 4 blocks or supports holding the corners of the trailer and tongue.
I loaded my boy last night and forgot the truck was not attached while working with him. It was very solid since the suspension no longer supports the horses weight.
No movement whatever.

This makes my daily practice alot easier and faster.
I ask him to load twice and if he does the load and unload perfectly that is all I do and put him back.
He is approaching the trailer is enthusism because he knows a treat awaits him once he is loaded, the butt strap done up and tied in the trailer.
Treat time

Take a few minutes, block the trailer in an out of the way spot and practice away.

I've seen it and done this way before and it always seems to work well.

I actually have the problem that if I leave the trailer in the pasture, unhook it, and forget to shut the back door, the horses will load themselves up...... I actually saw my 3 yr old one time walk in our 16' trailer all the way to the front, saw there wasn't any food, and backed herself all the way out of the trailer instead of turning around.

I have used your blocking methods while training to load though, many don't think about it.

I would never load a horse in a bumper pull trailer without the trailer firmly attached to a vehicle.

The safety of the horse (and me) is more important than spending a few minutes hooking and unhooking the trailer.

But then again - I love my gooseneck trailers. I can hook up in less than five minutes.

I'm lucky enough to use truck only for towing. So I just keep them connected 95% of time.

Just wondering how do you teach to load horse with the bad experience in trailer in past (if you had any like that before)?

My truck is my daily driver so I need to unhook every time.
I have trailered alot of problem horses. I also ride problem horse. I have trailered hundreds of miles for a pickup, never saw the horse before, I am being paid for the pickup and they can't load the horse. What do you do?? Turn around and go home?? Charge the person anyway???
Or get tough and load that horse quickly???
I have never gone home empty and once I decide to take over the loading at the owners permission the horse goes on regardless.
It is all in how you position the trailer and the options you give the horse.

Yeah, that was exactly my question, actually...

Pick a solid wall of a barn or any building. Put the trailer on a slight angle until you are almost touching the building. There is no escape in that direction and the horse can not get between the building and trailer. That leaves the one side and behind the horse. A pair of buggy whips covers that area and make it so the horse chooses to enter the trailer, it is the escape route for him and nothing else.
Never had it fail.

That's an interesting approach. All I've heard about is just working horse like crazy or spend 2 months on in/out one hoof in time.

Depends on what the bad experience was.

Often the truck driver is the problem. They forget to slow to a stop, pick up a steady speed and take turns wider.

If we need to pick up a horse unsure of loading, we bring our large stock trailer. Very open and airy. It also has mats so it is not noisy and scary.

I don't have 2 months. I am away from home on a pickup and I am perfectly willing to tour the place for say 1/2 hour while the owner or groom loads the horse and then I am off but after that time and with the owners permission I put the horse on the trailer and I am off.
I have picked up young horses 3 and 4, wild, with no training and had to trailer them to some other farm and so far I have never had a real problem loading them. They were born on the farm and now sold so this is their first experience and my first time being introduced to them.
I can't afford too much time or it isn't worth my time to do a transport.
My trailer is now 23 years old and in mint condition with never having a horse destroy it

Also take the case of a sick horse, one needing to be taken to a medical fascility and the horse is a non loader.,. How else do you get them on the trailer and off to the hospital??
Try it with a problem loader. One side up against a building, no place to go but on. Without the building the horse will just run off to the side and running a lung line will not work.