Proper bike fit is the first thing to get right, then you need time in the saddle to give your body time to adjust. Anyone who goes from occasional rides to a long period of 40 to 60 miles per day is asking for trouble.
When I have been off the bike for the winter, I know that when I get back on the bike I will have soreness for 3 or 4 weeks as my backside gets used to the saddle. No combination of saddle, shorts, and bike fit will prevent this soreness, it's completely normal. I would not attempt any long rides without at least 6 weeks to prepare. Unless you have some physical impediment, any combination of a decent saddle,shorts, proper bike fit, and time on the bike will eventually cure soreness.