Obviously someone living near a potential raid target would be more concerned than someone not, but would people read about it a lot (more than some occasional blurb) in papers and so forth? Would it be a likely topic of current events discussion?
Did anybody (or, rather, some meaningful number of people) think they'd have some success convincing the American government to take a stance on the English in Ireland and were they worried/enthusiastic about the possibility?
Or was it as much a blip on their radar as it is to most people today, usually coming up in hindsight discussions about burgeoning Canadian nationalism and confederation and that's about it?
The Fenian Circles of the Comstock (Virginia City, Gold Hill, and Silver City, Nevada) were fully involved with the 1866 raid. They began having meetings, and they raised funds and began drilling and target practicing. Local newspapers covered the raid as well as the local activities. There was a great deal of excitement and optimism that the raid would succeed and that the approach to winning independence for Ireland would work. When it failed, everyone went back to their lives, although the Fenian Circles remained somewhat active for the next few years. The subsequent raid was looked at with less excitement.
Considering that the most 'successful' raid, the Battle of Ridgeway, was heralded as motivating the up until then skeptical subdivisions of British North America (Upper Canada, Lower Canada, the maritimes, etc.) to join in Confederation and declare themselves the Nation (or technically, Dominion) of Canada, a year later in 1867, I'd say it had some impact.
That battle is indeed otherwise known as the 'Battle that made Canada'