We've traveled from IL as far west as AZ since 2005. We hauled up to 13-14 hour days although we prefer not to trailer more than 12. We only stop long enough for fuel. I would never suggest unloading the horses. We drop the windows and open up the back door for ventilation and scoop manure. We don't leave the trailer unattended with the windows/screens/bars down and open back door though. As for brand inspections, we actually got stopped by a brand inspector traveling through NM. No big deal. Just be sure to have your Coggins and health papers which are only good for 30 days. You want to be in compliance. I used to fret that the horses didn't drink or eat while traveling. No grain in the morning but I do administer a probiotic to ward off colic and ulcers. Been traveling like this over the years, and knock on wood, the horses have always fared real well.

We always stay overnight along the way using http://www.horsetrip.com/  and http://www.horsemotel.com/ and have met a lot of great folks doing so. Happy travels.

You will need Brand Inspection, Coggins and current health certificate.  Coggins are good for 6 months or 12 months depending on the state. So to be safe, I would make sure your coggins are dated with in 6 months. 

Health certificates are good for 30 days, But usually only list one destination. So list the farthest point you will travel to.  Some states will require your vet to call ahead and get a permit number.  I know if I cross into Montana, my vet has to call Montana and get a permit #, But I don't need to do this for Wyoming or Idaho.  Colorado periodically impliments this procedure if they hear of an outbreak of certain diseases. My vet seems to be aware of these procedures. I suspect he gets a bulletin that is faxed, emailed to him letting him know what the current status is for travel to surrounding states.

Brand Inspection,  Is basically proof of ownership.  Utah issues a temporary, 1 year and lifetime brand inspection, each for a different price.  It's just a pocket card with a description of the horse signed by the area brand inspector. Newer brand inspection now have a digital photo printed on one side.  I've also used breed registration papers for proof of ownership.
But basically have something in your possession from your home area that details the color and markings of your horse. If your vet does a good job, your Coggins and Health Certificates should describe your horse.  Some states like Wyoming want you to stop and have a brand inspector look at your horse and approve their entering the state. You can check their respective websites for rules for each state you plan to cross.

Any public land,  ( Forest Service, BLM, State Trust lands, National Parks etc) will require you to have certified weed free feed. So the only time you can feed non-certified feed is when you are on private land.

Port of Entries as you enter each state will want to stop and come inside, They usually want to you to fill out a form that details where you are coming from and where you going and to list your coggins and health certificate numbers.

As far as travel.  I usually stick to less than 11 hours in the trailer. I try to find fair grounds, public land or private camps to stop and get the horse out for the night and let them stretch their legs. During hot weather, I often stop at Fairgrounds and put the horse in their wash rack and get them good and wet to help them stay cool.

A lot of the states back east don't have Brand Inspectors.  So you can't get a brand inspection done in your home state. I know here in Utah, I need to document the purchase or birth of a horse to get my brand inspection. Hence the registration papers are my main source of ownership.  It shows that the horse was born on my property or that I bought and transferred ownership.  Bring something that is more than a handwritten bill of sale.

It's too easy to steal a horse and write a bill of sale note. Something that is dated, with a description of the horse ( photo is even better) will be better than nothing to help establish your ownership.  Then you can stop as you enter a western state and buy a brand inspection

Certified hay in Utah is $1 to $2 more per bale than non-certified hay and is available at most farm stores. Farm stores are more expensive than buying from farmers, But it is just too hard to find which farmers actually grow the hay. I pay $8.00 to $9.00 for certified alfalfa.  It is really hard to find certified grass. Anything certified is almost always going to be Alfalfa here in Utah.

Most processed feed. Such as hay pellets will meet the certified rules.  Since the heating and grinding involved in making pellets destroys the seeds. So if you can't find bales of certified hay, you can easily buy pellets at any feed store.

Hay Cubes are not always certified, since they don't grind the hay as fine, It is usually just chopped and then cubed. So it will usually say Certified on the bag meaning it came from certified hay before cubing.

The rules apply to ALL public lands, Forest Service, BLM, and State Trust lands. These make up 74% of Utah. So certified feed is needed at almost any trail ride in Utah.

Bring pellets from home and buy certified hay here in the west as you travel. I've seen folks bring certified hay they bought in the mid west and it looks pretty nasty in comparison to our wonderful hay.  Growers back east don't understand the rules and you get in trouble.  Each bale should have a certification tag or strings. Since the law enforcement officer in Utah may have no idea what color string in Nebraska is used for certification, It can be hard to explain.  And a single letter for 20 bales just doesn't cut it. Each bale needs to be marked by something that is recognizable to  an officer here in the west.

It just depends on who is looking, what they want to see.  National Parks, Rider organizers etc want to see the Coggins to make sure you are bringing healthy animals.  Port of Entry want to see the health certificate for travel. County Sheriffs and others involved stock theft want to see brand inspection and health certificates. 

So most trips it's just the health papers that ever get looked at. Most park rangers could care less about who owns a horse. There concern is transmission of contagious diseases and the spread of weeds. 

The bottom line is, If you need it and don't have it.  Then you could be sitting on the side of the highway in the hot sun while the officer figures out what to do with you.

Arieldouglas  Try a different browser.

There are several website that I have problems with when I use Internet Explorer,  For those sites, I switched to Google Chrome and the problems went away.  Some of the web designers that I know say they are just having fits trying to stay compatible with all the web browser that are now available.

Electrolyte tube paste morning and evening works great on my horse along with every 3 hour stops for 20 minutes to offer water and for horses to catch a few zzzz's.  As someone mentioned above, I carry the compressed Alfalfa, hay cubes soaked in a gallon of water, beet pulp soaked in water and then carry regular hay.  I get the Alfalfa and hay cubes from Tractor Supply.  All the "soaking" along with Electrolytes keeps them well hydrated.