Welcome to Allnurses!
The "best" approach is probably different for each & every person. I was lucky enough to have a spouse bringing in a paycheck after I quit my full time job as an engineer prior to going into my accelerated BSN program ~5 years ago.
I'd urge you to do your best to go the accelerated route. If you have to leave your job, you'll be without an income for the 12-18 months needed for your accelerated program (plus the time needed to get a job upon graduation). Think about looking into student loans to help pay for tuition & room/board while you're in school. Ask your schools if they offer any sort of scholarship to help cover tuition. In my program, if you scored over a 1100 on the GRE, you were eligible for a Graduate Scholarship (which covered up to 60% of the tuition), and if you worked ~16 hours/week as a grad assistant, the remainder of the tuition was waived.
Note that even if you go the accelerated route, you may need to take some prerequisite courses (stuff like A&P, micro, pathophysiology, genetics, pharmacology,...) before starting your accelerated program. Check with the program adviser for prerequisites. You should try to knock these prereqs out of the way if possible before quitting your job. You might be able to take some of them online.
If you go the standard 4 year BSN route, and you try to do that while working, you will probably NOT be able to do it while working full time. In nursing school, you'll need to have total scheduling flexibility to take nursing classes when & where they're offered. Trying to fit that into a work schedule may not be possible.
In my accelerated program, some of the students managed to work part time during the program. One guy continued to work full time as a youth pastor while doing the accel program. Needless to say, he was very very busy. Another member of my class was a mother to 3 or 4 kids, and was also active in the military reserve. She kept up with her Reserve obligations even while doing the accel program.