The best option for you depends a great deal on what you want to do as a nurse. Do you want to care for people, to be at their bedside, or do you want to manage nurses, the department budget, etc.? Perhaps after years in finance you don't actually want to have those managerial responsibilities to take home at night, but want to work your 12-hour shift and be done (you can find a lot of information about the different nursing roles online, including first-person accounts on this website). I originally thought I needed the BSN because I wanted the career flexibility to do management. Then I remembered that, in addition to wanting to have a meaningful and nurturing career, one of the reasons I left the communication field to go into nursing was so that I could leave my work at the hospital, not bring it home! I want to be in clinical practice, so I should find the best clinical experience and stop worrying about what degree I was getting.
If you definitely know you want to go into management, you will want to get your BSN, either right away or later on. The one thing I would not recommend based on your post are accelerated BSN programs, only because they are very intense and would likely not give you the flexibility to keep working. I think the easiest thing would be to enroll in a local college or university's BSN program and take it at your own pace (accelerated programs require you to take a specific courseload and specific sequence --there's no dropping a class or taking an extra year to finish your degree at a slower pace).
The best advice I received was from a nurse with 20 years of experience who told me to focus mostly on two things when choosing a school -- the school's NCLEX pass rate and the amount of clinical time offered. Both were strongly in favor of a hospital program in my case. With no previous clinical experience, I thought the most important thing to do was to make sure I was well prepared to be a NURSE. If I want to do management later, I can always do more classroom time, but never more clinical.
One last thing -- for all the programs I have researched, science courses (A&P, chem, micro, etc.) are only acceptable for 5 years after they are completed. So unfortunately, no matter which way you go, you may have to repeat a few courses.