List the dangers that might be a possibility on such a journey. The covered wagons have a limited amount of space. The average space is 4'x10'. Your mother has shipped heirlooms and precious keepsakes along with extra bedding and clothing on a boat that will sail around the Horn . Oxen were chosen to pull the wagons.
Oxen are strong and can withstand the difficult trip.
Mules are preferred by some because they are faster than oxen. The horses are along because they are needed to start the future ranch. Horses are not a good choice for pulling wagons. Horses get weak and need more water and food than mules and oxen. The family needs to pack bedding, tents, clothing and groceries , tools and ammunition.