The Senators do little to nothing, that means Cotton, Lee, Cruz, Paul, all of them. Cruz has set himself up to be the Conservatives Conservative yet, it is a fairly public veneer, he has not had to actually do things such as any of the governors who ran like Perry or Walker. Already, we are seeing Cruz put up on his high horse; and a lot of folks otherwise, are too good to vote for the nominee.
The problem is that unlike the governors you mention, Ted Cruz, Mike Lee, et al are a small minority in a much larger group,the vast majority of which don't give a flying fig about the voters who elected them. But take a look at the legislation Ted Cruz has sponsored and co-sponsored and his votes on legislation sponsored by others. He has done his best to represent the people who voted for him. If that legislation failed, the blame belongs to the liberal Republican crooks, not to Ted Cruz and his allies.
As for being too good to vote for the nominee -- hogwash. It's not a matter of being "too good." I for one would have been happy to vote for the nominee if I thought in good conscience he was right for the job. But IMO, neither Trump nor Hillary was right for the job. I am not going to vote for anyone I think is a lying, cheating, incompetent scumbag. Contrary to what you and others might think, we have more than just two choices in an election. And I think you are going to see in future elections, more and more people are going to look beyond those two choices. You can blame Trump and his rabid supporters for that. Whatever happens -- even if it turns out to be complete Democrat rule in 2020 -- Trump and his worshipers will own it.