How can I see all the data that solr is indexing?

Luke may help: https://github.com/DmitryKey/luke. You can point it at the Solr index and see what's in there.

Last time I checked, you could run it right from the web and just point it at the index.

As rfeak said, you can use Luke to inspect your index. Solr comes with a built-in Luke handler.