THE DATA
The ARCVIEW feature data in http://www.esri.com is TIGER census data, US street data, hazardous site data and USGS topography maps.  (Don’t get too excited about the topo maps – they are typically NOT free.)  This map was produced with TIGER census data from this site.  The best way to know what the layer filename prefixes are is to print out the readme file that gets downloaded with your data.  Note that there is also feature data available that comes with ARCVIEW and is typically contained in the ESRI directory in the ESRIDATA folder.  All of this feature data is georeferenced in decimal degrees.

THE OVERLAY
In order to use raster data of any kind (as opposed to vector feature data), you must have the spatial analyst extension clicked on under file – extensions on the menu.

With your TIGER data loaded in as multiple themes in a project view, bring in your .dem raster grid files by adding them as a theme.  (This assumes that you already have them in .dem format – which I will explain how to do in the next image detail write-up on the webpage).  Go into View – Properties and change the projection to match the properties associated with your DEM file.  In this case it was UTM – NAD 1927 (zone 10) with map units in meters.  You can get this information from either the map itself or the metadata file that comes with your data.  You may set your distance units to whatever you want your measuring tool to measure in (it is not specifically tied to the map).  Once the themes are loaded and active and you have fixed the view properties to be consistent, you may have to click on view active layers button to see it all together.