As long as you have a plan for emergency situations, you don't HAVE to have a truck and trailer.
(I know that some of these won't apply but thoughts anyway:)
What if a wild fire or prairie fire blows through your area, and you need to evacuate your horse immeidately? Will you still be able to have a friend get your horses out? If not, figure out a strategy.
What if a flood takes over your land? Again, who will haul your horse and where will they go?
What if your horse is injured and needs veterinary care? Can the vet come to you?
Try to think about every possible emergency situation that would apply to you, where you would need to haul your horse. Then have a plan in place.