I have just started commuting regularly 18.5mi each way to work, 4 days a week, on Monday OR any day I absolutely need to drive in to work I will bring some clothes into work and swap out my smelly stuff. I've also done 21-22mi each way here and there as needed due to traffic or bad weather, depending on the elevation you're facing it may not be a good idea to do quite that much. I have about 1200ft of elevation going and 800 or so coming back, after a few days it does start to hurt with the extra weight I'm carrying. So I'd say just do it a few times a week, and do a recovery ride the other days from home in the morning or evening.