Indiana Jones--this usually goes fairly quick--under 15 minutes usually, including the ride. You will go in the exit, and veer to the right at the rope (it's obvious), then they will lead you where to go. You're with the regular line up the incline, then follow the HA line into the elevator.
Matterhorn--this one can be a roll of the dice--we've been through it as a walk-on, and we've waited 20 minutes. But, usually less than 10 minutes.
Splash--this one gets confusing. It often gets mixed up with the HA line, and so the single riders think the line is terrible. I'm not complaining

Makes the real SRL a lot shorter!
Goofy's Sky School--usually short, but you only get a seat when there's a group of 1 or 3 (or other odd numbers). Longest wait I've had was like 5 minutes pre-ride.
Screamin'--a confusing line (there's 2 places you wait, once before the elevators and once after) but tends to move at a very fast pace. Don't pay attention, and you'll be overlooked and people will go in front of you. Longest wait I've had was like 10 minutes, including the ride.
Grizzly--my favorite on a hot day--I've never waited more than 10 minutes in line.
Radiator Springs--this one can suck. It's well-marked, it's well-known, and it's a long standby/fastpass line, so people use the SRL continually. I've waited upwards of 45 minutes in the SRL here. Part of the issue is the people in the SINGLE RIDER LINE begging cast members to seat them with their friends who are also in the SRL....