Well done man, made my day to read this thread and see your determination.
Just a couple of tips that could go a long way bro:
1. Don't view cardio as 'exercise' or 'cardio' - i.e. a means to an end product alone. You are in a unique position in that you get a little more spare time than most, so instead of doing fucking 'excercise/cardio' every day, pick something you love doing (or start something new outdoors) and do that shit everyday!
What you will end up with long term is not 'cardio' to burn extra calories - but your actual LIFE will be different. Your LIFE will need MORE calories to sustain all the fun shit your doing everyday.
2. I'm only 30 years old, but something i've noticed in life along the way (call it karma/reaping and sowing whatever): If something took a long time to build.......it's going to take a long time to take apart again.
Basically what i'm saying with number 2, is double the amount of time you want this to take. If you get there sooner - bonus.
Fucking kill it man.