OK, Ron, you figured it out - we do have more than one horse. Three, actually, but even though one of them is mine, they all happen to be registered to my wife. So, maybe I should change my name to "NoHorse" or "Wife'sHorse".
Back to your question, I have mapping software up the wazoo. I have the DeLorme Topo USA, but mine just covers the mountain states, also National Geographic Topo which covers the state of Montana. I also have all the USGS topo maps of Montana.
It's nice being able to do a hike or horse ride using the GPS along the way, and then be able to dowload it into the mapping softare for a record. Also, can work it the other way around, where I map out a route on the computer, then upload it into the GPS. When I get to the trail head, turn on the GPS and follow the track that I entered. Lots of fun, but also can be really useful.