Sounds like a wiring problem. Speakers typically go dead if one of the speaker wires is shorted to ground. You've already told me the radio operates other than the fact you have no sound.
The most common problem with the clock is that there's an internal problem. It's easy enough to check for proper input. You've got one wire for ground, one for constant power, one for ignition switched power, and one signal wire from the lamp switch (which controls whether the clock dims).
The most common problem with headlamps is the bulbs themselves, even if both are out. Start there. Then, if the bulbs are okay, check things like relays, switch, and grounds.
The bad news is that if there's a common cause for all the items, it's likely chafing wiring somewhere behind the dash.