When you enter your route into the FMC (which im still struggling with a bit) do you still have to use ATC?
What do you mean "do you have to use ATC"? You mean single player FS2004 ATC? I suppose you can, but eventually (when they vector you for approach), you will have to abandon your flight plan. You could just not use the ATC, but then traffic might be an issue. Or - better yet - fly online 😉
Yeah, the default ATC will garuntee to vector you off the wonderfully organized and planned STAR's and approaches for some reason, so your best really is to fly on line with those things. It can be a hassle making last minute FMC adjustments (which VATSIM operaters usually love to do 😉 ), but you really get to make full use of the thing!