I'm in the middle of it currently. My experience has been that doing the ATPL's was tough, but doable, as long as you are dedicated. What knackered me out was using all my holiday for a year for groundschool and exams - when I finally passed the last ATPL's I took a week off to do nothing & recover.
What's consuming my time now is the availability of slots to complete the CPL (got my 170A coming up this Saturday) - it's not dedicating the time - it's the weather being flyable when you have slots booked. I know this is beyond our control, but I literally lost 6 weeks of time due to dodgy evenings / week-ends.
I'm hoping to start the IR in the next few weeks, and hopefully that will, by it's nature, be a little less weather dependant.
It's definitely doable, just needs dedication, and a little luck with the weather!
Cutoff - do you mind sharing where you found to do an evening MCC - I've found several that will be quite flexible, but they all still need some time off.
DW.