I caution folks on feeding sweet feeds, salt blocks, sulfur, or hard mineral blocks. Simple is usually best--grass hay, water, minerals.
Beyond that, you might think about what they will have access to eat aside from what you provide. Here is a link to a list of potentially dangerous plants that you should avoid feeding your goats.
In general, avoid letting them have rhubarb, azalea/rhododendron, and yews. Take a look around where they will be and note the types of plants growing. Many of the items on the list require the goat to eat a lot of before they would have an issue, so if you see there might be a problem with say TONS of milkweed, you might work to reduce it.
http://www.ansci.cornell.edu/plants/goatlist.html