Even if you are online, you should plan for SIDs which end with your first waypoint and STARs which begin with your last waypoint. Their purpose is to take you from airport to airway system and back. If there is no SID/STAR connecting your airport to your desired first/last waypoint, then you have to choose a different waypoint. Of course there are places where SID or STAR ends or begins in the middle of nowhere - then you should choose the one where you have the shortest DCT path to your first/last desired waypoint and ask ATC for clearance up to your waypoint, not just only for SID (same on the other way). If you have a SID which barfs you out to north and you want to go to south, you would probably have a clearance for SID and then "expect vectors". What would you do during a COMMFAIL? Overfly the airport through a busy TMA? There are countries where TMAs are Class A airspace (e.g. the country around EGLL), controllers wouldn't be hapy if they had to clean all that airpsace for you . In some countries, there is usually only one SID/STAR connecting airport to a waypoint (I believe that this is true in Germany, where controllers prefer you to write the name of the SID/STAR to the route of your flightplan, at least on IVAO). Then you know in advance which SID/STAR you would get. In other countries there are multiple SIDs/STARs for airport-waypoint combination, usually one per runway. Then you have more to choose, depending on active runway - but if you know the winds (or get the METAR), you probably know the active runway and can predict the SID/STAR which you would get from ATC (or from yourself when either you or the ATC is offline).