Metadata
We document the translation from RDBMS to Neo4j as a Metadata Graph Database itself.(note this doesn't persist any data from the tables)
Data Import
What I do is I usually model the ETL process from RDBMS to CSV using Talend, which has a built in ETL mapper. The "tMap" component in Talend, gives you an understanding of the translation from your entity to csv, which inturn relates to Neo4j nodes/properties etc.
Then I load the CSV into Neo4j, using Talend to import CSV into Neo4j database.