Hi Franklee,
The best goat breed for all pasture low imput husbandry, is the breed Kiko. They are a meat breed with all forage, zero imput breed standard. Meaning cull for parasite problems, feet problems, mothering problems, slow growth rates, or even bad instincts. Essentially make sure they have good
water, good pasture/forage and preditor protection.
Without fencing you may need a herding dog that is trained in the boundaries, if your goats are prone to wandering to far. You may also need to train that herding dog to bring them in at night, which is the easy part. Though if raised from kids being sheltered at night, and given quality grass
hay, or have some free choice supplement treats like kelp available: the goats may naturally come in at night. The herding dog best suited to the spacific task of maintaining boundaries, are in the German Shepard lines, spacifically breed for herding: as they are often trained for boundary work. Im not sure how well they would do unsupervised though, as some working breeds will work themselves do death. So it would take time to train the heard, the dogs, and properly evaluate if they can be left to work unsupervised. A unruly herd can work a good dog to death. There can also be issues that arise between LSG dogs, and herding dogs. Meaning sometimes the LSG dogs will stop the herding dogs from doing their jobs by perceiving them as a threat. So to implement your plans will depend on the goats themselves: how far they wander, the natural barriers like streams which may prevent wandering to far, how the herd reacts to the herd dog, how the LSG reacts to the herd dog, and the breed of goat you choose.
Kikos are strictly a meat goat. Though in one trial a kiko out performed one breed of
dairy goat in milk production, but that doesn't mean the milk was desirable in flavor. Kikos will average 1.75 kids per year, if you keep the billy back to time your kidding for late spring, alowing only one kidding per year. If you alow the billy to breed year round, they will have more kids, but at bad times requiring intervention: which isn't recomended in areas with distinct winters.
Hope that helps!