Let me start by saying that I really like TopoFusion. It's a very nice application that's versatile, powerful, easy to use and is a bargain for the asking price ($40 as I write this). I use it for all my post-ride analysis and some ride planning as well.
Post-ride analysis What I do most with TopoFusion is to look at my ride when I get home. I hook up my GPS to my PC and, using TopoFusion, download my track log and save it as a gpx file. My ride is then displayed on a map with color coded relative elevation. I also get a whole bunch of data such as: ride length, moving time, total climbing, average speed, pace, and grades. I may also look at my climbing profile (an export of the profile display is included with each of the rides here). I enter some of this data into my logging application CycliStats. It's worth noting that TopoFusion does include a pretty good log and it may be fine for your needs.
Racing myself There are a number of rides that I do frequently. With these track logs, I can race against myself after the fact. I simply load several of the track logs and then use the Multi-Playback tool. Be sure to set the Track Color to be unique for each track log. I turn off the Auto Zoom and Auto Follow functions and zoom out the map to see the whole route. When I start the ride, I see all of my rides take off, racing against each other. It's nice to track my progress this way.
Digital Elevation Model (DEM) Before I dig into some more advanced topics, I need to explain a little bit about DEMs. In short, a DEM is a digital representation of the topography of the earth's surface - they show terrain. Topofusion will use DEMs for altitude data. This is very useful in pre-ride climbing analysis and 3D modeling. DEMs are readily available in 30 meter resolution, but we have 10 meter DEMs (more detailed) for all of Utah. Utah DEMs are available and a map showing which files you need is here with more details here. Be sure to restart TopoFusion after downloading a new DEM so that it can add the file to its index.
Pre-ride climbing analysis Now that you have the DEMs you need, you can get a feel for the elevation profile of a ride you're planning. For starters, you'll need a planned route that you can load into TopoFusion. I create this with MapSource, but you can use anything that will output a GPX file. This route needs to have its waypoints spaced about equally apart and with mostly straight road in between them. Once you have the route open in TopoFusion, right click on it with the hand icon and select Spline/Simplify Track. You want to Add Points. What you're doing is adding a configurable number of track points between each of the track points already in your route. The more track points you have, the more accurate your elevation profile will be - that is until you exceed the resolution of your DEM. Play around with the values and you'll find what works best for you. I've done some test rides and compared the pre-ride profile to the actual profile afterwards. The more linear the profile, the more accurate I've found it to be. Keep in mind that this is only an approximation intended to give you an idea of what you're getting into.
3D modeling Another things that's fun to do with TopoFusion is to view your ride in a 3D map. If you have the DEMs for the area of your ride, bring up your track log and press the 3D button. This brings up a fully interactive 3D map with your track log. This is way cool
There are a lot more features in TopoFusion that the few I've touched on here. I strongly suggest going to the TopoFusion web site and checking it out.