$740.. Is an OUCH! But it sounds right close to what I'd expect.
Might be cheaper to pop a Honda EU-1000i in the bed of the pickup and plug in a PD-9260 to charge the battery... Though depending on the time of day (Day/Night) and weather that might be a bit anemic... Still. the fact that the Honda can charge 'er up while the truck is parked makes up for it.
(joking of course) Now a EU-2000i with a larger converter... Well that's too much for the truck's battery to accept.
Oh, and as for a volt meter..... Alternator failures are a bit like fuses.. one mile as you go down the road it's working perfectly... The next it's working not at all, totally dead.. At least that's how it usually works.
And the ABS light is often your first warning.. IT's one of the most voltage sensitive devices on the vehicle so when the voltage starts to drop the ABS alarms.. Next is radio in many cases. (not all)