What you decide to use depends on many factors. Funds available, distance to travel, number of alpacas to transport, time limitations, etc.
Alpacas tend to cush when the vehicle they're transporting in is in motion so they don't need a lot of room for a short trip to the vet or neighbor's. Alpacas are easy to train to load and unload. The main thing they tend to be afraid of is that "big" step/hop up into a trailer or the back of a van or SUV. A ramp helps, but so does patience. Keep practicing and don't push them too hard or too long and they'll figure it out quicker than you think.
Just remember, the safety and comfort of you and your alpacas should come first.