My remote loader and JDBC for MSSQL driver both start, but there is no
indication that either can see the other.

I've verified the IP address on each. Verified the Remote loader port.
Verified the MS SQL Database port.
I've installed the 3rd party MS SQL JDBC driver files to the SYS:\system\lib
folder. msbase.jar, msutil.jar, and mssqlserver.jar

That seemed to be enough when I was configuring JDBC to Oracle. Any ideas?