It sounds like all the symptoms experienced by a friend on his 916 a couple of summers back, it was his regulator dying slowly over a period of 2000 miles through spain and france the electrics slowly went to electrickery heaven in the last 500 miles, indicators failing, going onto one cylinder, fuel pump, revs not showing......................replaced the item when returning home following the last 300 miles on the back of an AA truck and all was well.
Good luck