Generally, astro-turfing (the use of a PR engine to create the appearance of grass roots support) is designed to get a candidate elected (or issue passed) that favors the money financing the campaign. We have seen a number of these in California and there has consistently been a strong correlation between benefit and later funding source analysis.
However, some really earnest but ineffective people were elected under the guise of the 'tea party'. Much to the disgust of the Republican Party power infrastructure (the speaker of the house cannot count on all of his own party's votes for that reason). Generally, power interests that are trying to manipulate the system don't throw random people into the mix like that.
My conclusion after looking at the folks who were elected that way is that a large number of them, perhaps the majority of them, were elected by people fed up with the system and not an interested third party.
But lets set that aside for a moment. Lets say you and your friends can get elected to city government. If your city runs well, and you don't put up with the baloney that sometimes passes as politics these days, you can parley that into county government. And that into state government. Assuming that you are good enough to learn the skills you need to make that trip. It can take you 6 - 10 years to go from city supervisor to state representative. Once enough people around you know who you are, you can chose to focus on local elections or national ones.
The starting point though is that in order for this to work someone with the idea of doing public service to serve the public and not their own interests has to step forward. Waiting for someone else to step forward has never been a good idea, either seeking out people and supporting their efforts or putting your hat in yourself are the workable choices.
This is diverging from your original point so I won't push it too hard... But you don't think this has more to do with the larger trend in GOP members of congress over the last few decades? There has been a pattern of primary challenges against moderates for some time; it did not start with the 2010 election, it was only slightly re-branded and allowed to have a majority after a 4 year hiatus.