Since you want to score BG at RoTR.
It really depends on when you arrive. If you want to drive you need to hit the HS tollbooths about 9:01. They open between 8:55 and 9:10 most morning and if you arrive too early you have to circle back around. This will give you plenty of time to park, get through security, maybe ride MMRR. Just be stationary right at 10 AM with a good cellular signal to join a BG.
If you get to the area early then you could check-in at YC, park there and walk over to HS. It is about 9/10s of a mile and can be quite hot some morning but you have more control of when you arrive at the security checkpoint at HS. You could also drive from the YC if you want allowing for the timing mentioned above.
The skyliner will actually take the most time since you have to walk to the International Gateway skyliner station, wait for it to open at about 9 AM, ride to CBR and change skyliner lines and get to HS.
Dave