tlist tool will list the starting command line and cwd for a process, or use ReadProcessMemory and PEB traversal, tlist and process explorer both do ReadProcessMemory and PEB traversal. I suggest writing some XS code, since doing ReadProcessMemory and PEB stuff with Win32::API is possible, but painful to parse all the structs, and remain 32 and 64 bit compliant.

edit: google says there is Win32::Process::Memory, dont know if it works, parsing the structs is the hardest job, not looking in another processes memory, also there is Win32::Process::CommandLine.