Hey Grasshopper,
I'm not certain, but it sounds like you are building a User Interface in C++ to operate your sequences, much like the one you can find at C:\Program Files\National Instruments\TestStand 3.1\OperatorInterfaces\NI\Full-Featured\C++ using MFC. If this is the case, then the way to get access to the RunState property is by utilize UIMessages. You should be able to do a search on the forums or in the Developer Zone and find some more information and sample code about UI Messages, but in a nutshell, you'll send a message to the User Interface that you are building by utilizing the ActiveX adapter (Action Step) in a TestStand sequence (The Method is PostUIMessageEx and can be found in the Thread class). When you send the data you will want to send ThisContext via the ActiveX parameters. You will then use the ApplicationMgr Control in your UI to register the UserMessage event and then create a function to be called when this event does occur. In this function, you can get the Sequence Context from the ActiveX parameter and at that point can handle it just like any other code module to get and set items within your locals, runstate, or whatever you want. That should give you a start, let me know if you into major issues.
Adam B.