Hi,
If you are using Integration Manager and eConnect or another import tool is not an option, then you can probably do a direct table import.
I use eConnect to import benefits and deductions, so I haven't looked at the tables, but it looks like for benefits, you will need to look at UPR00600 (Payroll Benefit Master) and UPR00601 (Payroll Benefit Based on Master).
You can either try and create your insert SQL statements directly, or you could use the zDP_UPR00600SI and zDP_UPR00601SI stored procs.
If you do use a manual import into the tables, I would definitely test the import on a test company first, and then perhaps run Checklinks to try and confirm that there are no obvious issues with the data.
Let me know if you have any questions.
Thanks,
Steve Endow
Dynamics GP Certified Trainer
Dynamics GP Certified Professional