in that you could precache the software so the clients could run it whenever they wanted to. However, in NS6, it was a significant challenge to manage systems outside the DMZ.
In NS7, everything is task driven, so the package isn't downloaded until the install time. There is an option to setup a managed software delivery policy, which when properly configured will download but not install the software (basically using a dummy command line). Once it is precached you can execute a task at a scheduled time.
The other option is to leverage the software portal, but I've never had to do that with mostly disconnected users, so I don't have any firm ideas if that will work.