Check grounds. Roughness may be due to dirty injectors, a bad fuel pressure regulator, vacuum leaks. Easy to figure out but hard to do long distance.
Cruzin performance has cleaned injectors for me on 2 cars that sat up like yours. About $100 to do a set of 4.
Is the clutch stuck on the flywheel or is the slave cylinder frozen? I have seen both.
If it is indeed stuck on the flywheel, pressing the clutch pedal and starting the car should release it. Also, driving it and accelerating and decelerating will do it with the clutch pressed pedal in.
More often, I have seen a frozen slave cylinder. Have someone depress the clutch pedal while you are under the car and watch for slave movement. If the slave is stuck, you can actually bend the clutch pedal and ave to rebend it back.