On the engine, the cable is held down in two places. First, there is a clamp toward the rear of the engine next to the kickdown linkage. Just loosen the clamp enough to slide the cable out. The second point is, of course, on the carburetor. It is held to the throttle linkage with a very small nut and bolt combination.
Replacement is, amazingly enough, reverse of removal.
The only tricky part is threading the cable through the firewall, but even this isn't too bad. Well, the too-long throttle cable was pushing us over the edge, so we called Totally Auto and ordered a used one. They were very friendly and helpful. The cable ends at this fulcrum under your right foot. We figured that while we were rejuvenating the throttle linkage, we may as well replace other worn parts.