Are you visiting yourself alone, or with family/kids/friends in tow?
If by yourself, i highly recommend the Single Rider line at RSR.
If with a friend and you are willing to ride separately you can still utilize the Single Rider line.
If you plan on visiting with a 3/4 people, or with kids in tow...the Single Rider line is not an option.
You CAN still ride however without waiting hours if you are not able to score a FP in the morning stampede.
Try riding in the evening, right before Park close.
RSR is beautifully lit in the evening (as is ALL of Cars Land) and in most cases as long as you are in line for an Attraction a few minutes prior to Park closing time they will cycle you through for a ride.
It may be different however at RSR, so i recommend showing up 30 minutes ahead of closing and getting in line or at least inquiring about it with one of the CMs at the entrance to the Attraction.
Others here may have more insights.
I have had no problems riding RSR the two times i have visited since it opened.
The most i have waited in the eight rides i have done to date was about 20 minutes, and i have never used a FP for it.
BUT...i visit *off season* and alone...so...your mileage may vary.
I find Single Rider is a blessing for RSR, Soarin* Over Cali, and the Matterhorn Bobsleds in particular.
I do NOT recommend it for *Indiana Jones Adventure* as you bypass the utterly amazing queue experience which is half the ride in itself.
Hope this helps!