When i did the raid Pyrenean and then the Alps via Ventoux unsupported in 2014 I used revelate luggage. For front lights I used a fork mounted LED flasher so cars could see me and a helmet mounted light so I could see. I mounted my garmin so that it was behind the bars and offset enough to allow turning without hitting my top tube bag. this also meant it was easy to run a power lead from my compact power supply to the garmin at the end of long stages when the battery was dropping off.
I run my Garmins on aerobars and use long right-angle cables from a battery pack in a top top bag to charge them. Need to get bike and work out dynamos...
When i did the raid Pyrenean and then the Alps via Ventoux unsupported in 2014 I used revelate luggage. For front lights I used a fork mounted LED flasher so cars could see me and a helmet mounted light so I could see. I mounted my garmin so that it was behind the bars and offset enough to allow turning without hitting my top tube bag. this also meant it was easy to run a power lead from my compact power supply to the garmin at the end of long stages when the battery was dropping off.