You can do this with a csv file and Visual Integrator.  This could be done with a script but as you are new to Sage 100 you would probably have to get someone to write the script for you. You don't need to know the latest Sales Order number or Purchase Order number as the system will pick that up for you. You can update a Sales Order or Purchase Order and if you want to update the lines you would need the line key.

Thanks for your reply, BigLouie!

However, our main goal is to prompt and/or run these scripts in an Excel based program rather than through the Sage 100 UI, so I'm not sure we'd have access to the Visual Integrator?

Actually you can call Visual Integrator from inside of another program.  How to is in the Help file. I have called a VI job from a button on a form in Access.

 This from the Help files:

You can execute a Visual Integrator job directly from another application. Microsoft Office products, such as Access and Excel, allow you to use the Visual Basic script language to execute external programs. Refer to the technical reference manual for the external product on how to execute external programs using their script language.

That's pretty neat! Just in the help file of Sage 100?

And for other reasons, we still want the ability to read the latest SO and PO numbers into Excel.

Can we do all of this without becoming a Sage Development Partner?

Read data using ODBC.  Import data using Visual Integrator (command line start of a pre-configured import job with a hard-coded source file name, or DSN data source).  None of this requires Development skills.

Read data using ODBC.  Import data using Visual Integrator (command line start of a pre-configured import job with a hard-coded source file name, or DSN data source).  None of this requires Development skills.

Any decent reseller can show you how to do this.