Terminal Services is the way to go if your sticking with Windows.
If these applications are so important that multiple people must access them then either buy more licences to run them locally on machines or put them on Windows Server and use TS.
Tell your boss not to be such a skinflint. You'll waste more money on lost time and productivity trying to find a "cheap" solution to this issue than you would spend putting the proper solution in.
Sorry to be blunt but that's how I see it.
Of course, if you were running this stuff on Linux you could do it for nothing.
