I think Hollywood got real cowboys mixed up with mountain men. Usually they had a horse and a packhorse. Carried their cooking equipment and flour, sugar, coffee, smoked or salted bacon, dry beans, and their traps. If you notice, especially east of the Mississippi, county seats with their towns are about 20-30 miles apart. If someone was traveling by horse, or horse and buggy, they could make it from town to town until they hit the plains and mountains, then they traveled by wagon train until the railroads were built. Even a person walking could walk 20-30 miles a day at 2-3 mph. For a horse rider with a bedroll could sleep along the way. Killing fresh meat would probably be much easier back then while traveling.