There are certain things you need to look for when measuring the honesty of liberals writing about certain periods. For the Progressive era, they need to admit that civil liberties often mattered very little to the champions of "reform." When it comes to the New Deal, they need to acknowledge that on the specific terms used to justify the New Deal — i.e. ending the Great Depression — the New Deal was a failure (the best recent conservative book on this point is Jim Powell's FDR's Folly). Moreover, they need to acknowledge FDR's numerous shortcomings in terms of personal honesty and intellectual heft. I'm not saying that you have to think FDR was a lying dullard, or that the New Deal was a bad thing, to be an honest historian of the period, but you have to deal with those allegations thoughtfully.Similarly, I find conservative books most honest when they acknowledge Reagan's numerous shortcomings in terms of personal honesty and intellectual heft, and his failure on the specific terms of the Reagan Revolution -- i.e., to get the government off our backs (though if you think Reagan's purpose was to allow corporations to raid the Treasury, you would be honest in calling Reagan a success).
As for the 1960s, you have to admit that at least some of the rebellion was little better than a pose; that fear of Vietnam and not high-minded pacifism was a major motive for the protest movement; and that some of the participants in the 1960s were either damaged people or became damaged because of their participation.
Also, you would need to admit that at least some of the Gingrich Revolution was little better than a pose; that enthusiasm for a new scam for disentangling suckers from their loot, and not high-minded government reform, was a major motive for the Contract with America; and that some of the participants in the Revolution were either damaged people or became damaged because of their participation.
Such books exist, but the conservatives who write them are usually called liberals.