Miscellaneous

You could try writing a custom action calling net use, but this would probably mean introducing fixed paths in your msi, so at the very least store the network path in a property, or try to find another way to map the drive (like a policy)

Use Logon script to map network drives

I wouldn't do this but would instead make it a prerequisite in your delivery system external to the MSI.  If the server changes or the location you map to changes, you'll need to update the MSI.  Also, SCCM delivers by default in the system space so a check for a user mapped drive will fail.  If you are a multi-site organization, you could be spanning the WAN by mapping a drive.  Finally, if you put the command to map the drive in your MSI, you'll also need to either code in credentials or provide them to your users - neither of which is a good idea. 

If anything, I'd use AD to ensure that the users were in the appropriate group to have access to the share, map the drive, and if in an SCCM shop distribute the app.