Is it possible to monitor what is happening to an Access MDB (ie. what SQL queries are being executed against it), in the same way as you would use SQL Profiler for the SQL
I'd suggest upsizing the tables to SQL Server. There is a tool from the SQL Server group that is better than the Upsizing Wizard that is included with Access.
SQL Server Migration Assistant for Access (SSMA Access)
Also see my Random Thoughts on SQL Server Upsizing from Microsoft Access Tips page