Susan,
Your project is a perfectly acceptable use for the link tools in Military Analyst. Keep in mind that these tools are extremely simple. Too simple in fact, and we are working on a more complete solution for a future ArcGIS.
Anyway, our test case for these tools involve a simple point features of cities around the world (acting as nodes) and a small table of travel routes connecting FROMCITY and TOCITY. The Create Links tool simple connects the city features using the table. The result is a set of line features that visually connect the cities. The Recalculate Links tools will update an existing set of lines (resets the connected cities if travel routes change). The Shortest Path & Critical Links tool takes the node/link network and finds the 'shortest path' between cities and finds any terminal paths (paths endpoint cities that have only one connecting link). Hope this is useful to you.
Matt
