The things that I have had break could not be repaired with tools anyway, so I don't carry any. Like, clutch cable, flat tire, advance mechanism etc. I do carry fuses and some tie wraps and they have helped me get home, including when my battery cable broke off the battery terminal. I was able to tie wrap it on. I had the side stand spring break as well...tie wrapped it up so it wouldn't drag. I did carry a 14 mm wrench and still do because you need that to adjust the mirrors when the nut comes loose and the mirror just drops down so you can't use it, so, yes, carry a 14 mm wrench, some tie wraps and fuses and I agree with the idea of carrying a cell phone, but just as important, check out your local towing companies to see which one is equipped to tow a motorcycle and at what cost over what distance. You can do some serious damage to a motorcycle if it is not towed properly.
If you have an alternator failure, then unplug the regulator because you don't need it any more and it draws a few amps to power the rotor. It will draw even more amps if the rotor has shorted, which is very common.
I do have a little mod that uses the headlight failure indicator to alert me if the alternator fails. An alternator failure is very insidious because the bike keeps running until you are 100 miles from home and it's getting dark and your cell phone battery is low, so you need to know as soon as the alternator quits so you can turn around or check into a comfy motel with a bar. Here is that circuit:
The headlight fail light will come on when:
1. The engine is not running.
2. The regulator fails.
3. The rotor fails.
4. The brushes fail.
It will not come on when the rectifier fails if only one diode is shorted, but you have 12 volts in that case to get back home. This arrangement also provides a bulb test function because the light comes on when I turn the key and kill switch on before starting.
In addition to the alternator fail light, I also have a digital voltmeter.
