First, a supportive spouse. They need to have 100% buy-in on what you are doing and why.
Second, an solid goal. Why are you doing this? Without this, you won’t make it far.
Third, a healthy mind and body to hold up to the strain. Before embarking on this journey, get your diet and fitness right; this will pay dividends during the working time. Also incorporate this into the routine so you can do it without thinking.
Fourth, give up all hobbies, etc. to spend whatever time is leftover with the spouse and children. I mean this. Your goal path is now your hobby.
I managed to do a degree in Nuclear Engineering while a Senior Enlisted on Active Duty, working 60-80 hour weeks and deploying for a year at a time, using these guidelines. It’s not easy, it’s not fun, but it can accomplish those goals.
In reality, I’d advise getting a lower demand job so you have more time rather than embarking on the type of journey I did. I’m comfortably retired now, and I look back at those years with some very mixed emotions.