Hi @curiagens
Thank you for reaching out.
The MCUXpresso supports these LPC MCUs. It supports the creation of new projects and import LPCOpen projects. All IDE releases contain LPCopen examples, here is an example path of the location.
C:\nxp\MCUXpressoIDE_24.12.148\ide\Examples\LPCOpen
If this does not help as much, could you describe further your issue with the MCUxpresso IDE? I will be happy to check.
Diego