We've rode it twice, and each time we got in line at the gates quite early (first or second family up at the gate). Then got in the front of line drop, and then rushed over to the subs. The first time we did this we were on the first sub, the second time we got on the second sub (I had a harder time rushing LOL).
To me that's the only way to go. When we've tried it before the park closes it always had a big line, so we didn't have much luck there.
This only works if you are going in for MM, or on a non-MM day. Don't bother attempting it on a MM day that you go in at regular opening. There will already be a huge line.