Tips to Make You and Your Horse's Vacation a Smooth Ride

First of all make sure you have a first aid kit packed.  It can make all the difference during an emergency situation while on the road.

The amount of travel time each day a horse can handle varies by situation. In general, most people get tired and worn out at about the same time, or sooner, than their horses. As a standard, eight to ten hours of traveling each day is not a problem for your horse. In some instances, such as rodeo contestants, horses are hauled for much longer hours with no apparent problems. Contradictory, some horse owners prefer to travel much less per day.

Make sure when traveling any distance or length of time to give your horse a 30-minute break every two or three hours. This does not require that the horse be taken out of the horse trailer. Just standing still and not traveling is considered rest.
One important aspect of traveling with horses is keeping your animals hydrated. Horses can be reluctant to drink when traveling, which can affect how much time to travel each day. Each break you should offer your horse a drink of water, even if you are repeatedly unsuccessful. Carrots are an example of a good source of liquid on the road.
It is strongly recommended that horses should not be unloaded from the horse trailer until you are in a safe, enclosed environment, such as your horse hotel for the night. It is generally unsafe to unload horses at strange locations or roadside stop, since horses are easily spooked. 

Do not tie your horse’s head on a short rein that keeps his head high. Allow your horse enough movement so that he can lower his head to clear his airways by coughing and snorting.
Minimize the possibility of colic by having your veterinarian give a gallon of mineral oil plus water and electrolytes  4-12 hours before long distance transport. Alternatively, feed him mineral oil in a bran mash.

Try getting your horse to eating soaked hay a month prior to the trip. Eating soaked hay for one day prior to and during travel will provide your horse with additional water.   Apples, carrots or wet bran mesh will also help to deliver fluid to your horse's system.  (However do not introduce these eating habits with in two weeks of travel.  Only use these methods if they are already part of your horses diet.)
If your horse is bad to reject foreign drinking water, try adding apple juice to the water prior to your long travel so that it is part of his normal digestive intake.  Another option would be to ensure that you bring enough water from home.

Things to Bring
Hay -- it is a good idea to bring along enough familiar hay from home to last the entire trip.
While most horse hotels have hay for sale, it may be different from the hay your horse is used to. Sudden changes is a horse's diet can result in colic.
Travel Papers -- virtually all horse hotel owners and some state border livestock inspection station will require current health papers for horses and proof of a negative Coggins test. These papers should be dated within 30 days of your trip.

These certificates and papers can be obtained from your local equine veterinarian. Your veterinarian should know what documentation you will need for your trip.
Occasionally, some horse hotels and inspection stations may require a brand inspection for your horse. This does not mean you are required to get your horse branded. A brand inspector can certify distinguishing characteristics on an official form to bring along as you travel.