A good lawyer can make a world of difference. The good ones are expensive but most of the time (especially on first offenses) they can have the charges reduced and quite often can even get them dropped for a plethora of reasons ranging from the officer's improperly following procedure to casting doubt on the accuracy of the breathalyzer machine to proving that the person was improperly pulled over to begin with (although in OP's case running his truck into a ditch a few feet from the bar will probably throw that one out
Either way, I think just walking in and pleading guilty without having a lawyer is the worst choice possible. This could have an effect on his life for several years (and potentially longer if he drives for a living, is in the military, etc.) so it is worth spending the money necessary to protect himself. If he can't afford one, at least get a court-appointed one. It is better than nothing and you might luck out and actually get one that is half-decent.