I have had some success accessing SharePoint lists with the ACE engine via ADO.net and OleDb, but a better solution may be to use SSIS or another ETL system make a more-accessible copy of the list.
http://www.connectionstrings.com/sharepoint/[
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Microsoft ACE OLEDB 12.0
Read, update and delete
Provider=Microsoft.ACE.OLEDB.12.0;WSS;IMEX=2;RetrieveIds=Yes;
DATABASE=http://mysharepointsite.com/documents/;
LIST={5999B8A0-0C2F-4D4D-9C5A-D7B146E49698};
The keyword "Database" specifies the SharePoint URL
The keyword "List" specifies the GUID value for the desired SharePoint list (list=table)
Query without specifying table names. Ie use "SELECT FROM table" or "SELECT FROM list" (same result from both).
I specify the name of the list rather than the GUID.