I was able to run the model with the Age-only Succession extension from the new Launcher widget! I found that the application uses relative paths and is expecting to run from the C:\Program Files\LANDIS-II\v6\bin directory. For production this shouldn't be a big issue, I just need to figure out how to install it in that location. My largest hurdle this afternoon was getting the application to recognize the .dll's for the extensions. They live in C:\Program Files\LANDIS-II\v6\bin\extensions. This line needs to be in the app.config file:
<probing privatePath="6.0;build;extensions" />
Again, this path is relative to C:\Program Files\LANDIS-II\v6\bin. For debugging purposes, I copied the extensions folder to my debug build directory and that seemed to work.
I also learned that the source for Edu.Wisc.Forest.Flel.Util is available under https://code.google.com/p/landis-util/. Per this developer forum post, https://groups.google.com/forum/#!searchin/landis-ii-developers/Edu.Wisc.Forest.Flel.Util/landis-ii-developers/cjQtf4z3emc/BWJ6HuAjeEQJ, this is the new name for the FLEL library.