If your butt is already acclimated to 30-40 miles a day in your existing clothing, you should be ok at 60 a day, but you might consider something changing to undies and shorts made of wicking materials with flat seams and a gusseted crotch. Personally, if it were a leisurely tour, I'd wear my undies and shorts, but if it was a hammer-fest, I'd wear my bibs.
The J&G Touring shorts are nice...though perhaps a little too baggy and short in the inseam for my taste. Walmart carries some good poly-blend briefs with flat seams under their Starter brand and work pretty well for me for rides up to 60 miles or so and are MUCH cheaper than my merino wool boxers.
If you go with bibs, the Performance Ultra brand is a good choice for the money.
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey