Every once in awhile a thread comes along that I can speak to directly. My alternator went out on my 2007 RTS at about 95k (just after the extended warranty lapsed, no surprise

).
But first, let me tell you about when my alternator went out on my old F150 about 30-40 miles East of Las Vegas... Twice. In both of those cases as the charge indicator slowly dropped I was able to drive all the way to 'Vegas and hit the NAPA and replace the alternator (I always carry tools on road trips). Note that I was able to drive over 30 minutes and miles after the alternator died.
Not so with the Ridgeline.
A barely perceptible whine had developed in the RL before the failure, maybe a month or two before. It was associated with engine speed, not road speed so I suspected something driven by the belt. A mechanic's stethoscope couldn't conclusively pinpoint the problem. So at that point in time I made the decision to drive it until things became worse and therefore definitive.
Part way into work one morning there was a brief howl settling back into a louder, but not a bad whine accompanied by the charge indicator coming on. I guess I found my problem. Hey, work's only about 5 miles away and the F150 ran for at least 30 miles, I'll drop the GF at work and head back home and fix it. As I approached work, I started noticing that I really had to get my foot into the accelerator to get any kind of power. Dropped the GF off, turned around and that's when the dash lit up like a Christmas tree.
Performance dropped to the point that I had to floor it to drive at about 5mph. Parked the RL in the work parking lot and called AAA for a tow back to the house.
Moral of the story: Your alternator goes out and you have 5 miles and/or 15 minutes of driving left in an RL, period.
Roak
Ps. Replacement isn't that difficult, just time consuming and it's pretty tight in there and it took some extensive maneuvering to get the new alternator in place.