We did not use the GCH entrance on our early DCA day. We stood in line (just over a week ago, sigh) at the main entrance.
We got in line just after 9 and there were only a few people there. If we'd been brave and stood at a different line we could have been first through a turnstile, but we were the second family at our gate.
At 9:30 they opened the parks, and we went over towards Soarin'. They do not STOP you at Soarin'. They stop you JUST before the big huge Grizzly at GRR.
So someone entering at GCH would have a bit of an earlier start at that rope, because those coming from the main entrance have to walk from the main entrance up to GRR. However, we were right at the rope, even walking from the main entrance. Not many people, at least on that day, entering from GCH.
Hubby was able to grab Soarin' FPs on the way, at approx 9:33 am. He went through the FP-getting area as E and I went along the main path, and we just slowed a tad as he got the FPs and came out the exit of the FP area, then we just headed on up the rise, past the GCH entrance, and then to a stop before GRR.
Then we waited a half an hour, the CM (who was amusing and fun) being helpful the whole time. If you have an early morning Ariel's breakfast, you go up to the rope, tell the CM, and they let you on through.
Then right at 10, the CM took the rope away (telling those at the rope to wait...those behind us wouldn't have known the rope was actually gone) had a countdown, and then we all started walking towards TSMM.
There does seem to be another rope, over along the wide path that would take you between bug's land and Wine Country Trattoria. I think that most people wait there, having no clue that there's the GRR area to wait in.
Anyway, if you want to ride Soarin', I'd probably go to the main entrance. Maybe create a reason for it...like you want to get a Peet's espresso latte from Haagen Dasz (they open at 8am)...so that your family doesn't think you're silly for standing at the main gates. Then go on Soarin' and then go on to TSMM. You won't be among the ones to just walk through the TSMM line though...you might have waiting involved. But it won't be anything near what it will be like after 10, when most normal folk think the park is going to open!
And no, not everyone knows it opens early. A family was chosen to open the park the day we were at DCA early, and shortly after being chosen, they LEFT! They realized what time it was, realized they'd "have to stay there until 10", and took off, even with people trying to tell them it was less than half an hour until they would be inside the park. It was sad!