Sounds good. Take a look at adding the PSAppDeployToolkit to your SCCM tools when you get the chance. Makes deployment so much easier.
As for the various environment variables, here's what they translate to in terms of standard Powershell.
$envCommonProgramFiles = $env:CommonProgramFiles
$envCommonProgramFilesX86 = "${env:CommonProgramFiles(x86)}"
$envProgramData = $env:PROGRAMDATA