In 2009 I did exactly what you're proposing. 2-3 flights per week, fit in around 30 hours of work per week. Study was on the train to and from work. Slowed down to one navigation flight per week for that phase.
I gained my GFPT (now RPL) in 4 months, PPL by 9 months, CPL by 18 months and Instructor rating by 2 years. So zero to CPL with FIR in 24 months.
The worst part were the CASA exams. Self studied the 7 CPL exams and passed in 6 months. It was damn tough juggling that and near full time work, but I had my wife's support and a ****load of determination
Good luck.