Here's an example of getting a setting an Environment Setting using WMI on a remote PC.

Try using Microsoft WMI Object Browser to discover what fields are in the returned value. Microsoft WMI Tools

Code:
 Function WMIEnvironmentSetting($hostname,$ENV,$Value,$Type)
	? "Function WMISetEnvironmentSetting:"
	? "	($hostname, $ENV, $Value, $Type)" ?
	Select 
		Case $type = "set"
			$WMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\$hostname\root\cimv2")
			If @ERROR <> 0	
				? "	Error connecting to WMI interface"
				$WMIEnvironmentSetting = 1
				?
				Exit
			Else
				? "	WMI interface connection successfull"
				$EnvironmentCommands = $WMIService.ExecQuery("Select * from Win32_Environment Where Name = '$ENV'")
				If @ERROR <> 0	
					? "	Error connecting to Win32_Environment "
					$WMIEnvironmentSetting = 1
					?
					Exit
				Else
					? "	Win32_Environment connection complete"
					For Each $EnvironmentCommand in $EnvironmentCommands
						? "	Current Setting: " + $EnvironmentCommand.VariableValue
						$EnvironmentCommand.VariableValue = $Value
						If @ERROR <> 0
					    		? "	Cannot set Environment Setting for $env"
							$WMIEnvironmentSetting = 1
							?
							Exit
					    	Else
					    		$EnvironmentCommand.put_
					    		If @ERROR <> -2147352573
								? "	Cannot set Environment Setting for $env"
								$WMIEnvironmentSetting = 1
								?
								Exit
							Else
								? "	Environment Setting for $env set to: " + $EnvironmentCommand.VariableValue
								$WMIEnvironmentSetting = 0
							EndIf
					    		
					    	EndIf
					Next
				EndIf
			EndIf
			?
		Case $type = "Get"
			$WMI=GetObject("winmgmts:{impersonationLevel=impersonate}!\\$hostname\root\cimv2")
			$Items=$WMI.ExecQuery("Select * from Win32_Environment Where Name = '$ENV'")
			For Each $Item in $Items
				? $WMIEnvironmentSetting=$Item.VariableValue
			Next
	EndSelect
EndFunction