During the week, it's usually completely dead. The longest wait will be for Volcano, but that should be walk-on or up to a 10 minute wait.
I usually get walk ons for nearly every ride if I head out on a Wednesday. If not, then it's at most a 3 train wait.
The huge downside about visiting on a weekday is that due to the lower amount of attendance, then they will operate a lower amount of trains as follows:
Intimidator 305: 1
Dominator: 2
Rebell Yell: 1 and only operating 1 side
Volcano: 2 (1 if it really is that dead)
Shockwave: 2
Hurler: 1
Grizzly: 1
Ricochet: still a fair number of carts
BackLot Stunt Coaster: 2
FoF: 2
Avalanche: Can't remember at this moment
Anaconda: 2 (unless it's really dead)
I think that's it. Of course this is subject to change is a train is undergoing maintenance leaving one train operation or no operation at all.