Update: Success! Was able to convert to OSM with Export_to_OSM.py, all was needed was to change some paths in the code. Uploads via JOSM using the Open, and Merge commands (I recommend also adding some tag so you can query these out later if you need to do anything with them), then Upload. Watch as I add more layers on www.openstreetmap.org!
Old Post: It now seems I'll be able to use OpenStreetMaps either as the repository and rendering system for the full campus map, or as a selective baselayer for national data (for directions). The answer will depend, in a large part, on whether I am able to get campus layers into OSM.
I have worked with multiple OSM editors: JOSM, markaarter, and the QGIS OSM plugin and none will successfully take a shapefile, allow import into OSM format, and then upload to the OSM servers. I have tried conversion to KML and GPX, since these are formats accepted by one or the other of these editors ... still no dice.
There are scripts and programs which were specifically created to convert SHP (and all kinds of other formats) to OSM. I've checked out some of these programs osm2shp, shp-to-osm.jar even gml2osm ... problem is that they assume you want to map all the shapefile attributes ... seems like it could be a lot of extra work to figure these out for every layer I want to upload.