Its a bit of a non problem really, tourists have found their way through the Gaeltacht for years, I dont think the odd confused tourist is much to be concerned about. Map makers, including google, should call places by their official name, saying that the placenames act is a bit rigid, The fact is most people know Gaeltacht areas by their English name, im led to believe this also happens by some locals in the gaeltachts themselves, so with the risk of being shot down perhaps signs in the Gaeltacht should be bilingual, the use of a sign is information so what is the point if it doesnt communicate effectively? After all if signs all over the state are bi lingual, in areas with no Irish too, the it should be equal? You cant change usage overnight, people will call it what ever they want ie Dunleary for Dún Laoghaire (even though Dún Laoghaire is the only name for it), even after 90s years simce it changed from Kingstown only a handful of people pronounce it properly
An interesting annomolly is in google you can search any place name in Irish or English & it will bring you there, but the name physically displayed is in one language (ie search Baile Átha Cliath it will bring up a map displaying Dublin), but some names are randomly in Irish ( on the app at least), ie Droim Conrach is displayed instead of Drumcondra, yet An Spidéal is Spiddle, there is no system to it, its jst random places!
In short I dont think we need to worry about names of places, we cant change what other people call them, we need to focus our energy on learning & speaking Irish and through our own usage will the proper names arise

ps I agree with Brian if maps used the official name that would help usage, if everywhere calls it Spiddal you cant blame a tourist for not knowing what An Spidéal is