How old are the kids? If they're about to go to college, maybe taking job B is a no-brainer because they're suddenly going to get very busy (very likely also during the summer, with internships etc). If that's still years away, will job B give you the flexibility during the school year to spend your time on what the kids need (driving them to practice, attending PTA meetings, etc etc etc)?
We're in the thick of it. :) Ages 7, 12, 14. Job B still gives some flexibility to help with day to day kid stuff. The main difference they'll see is later days (not crazy. 5pm instead of 3.30pm) and less summer time with dad.
It's going to be a personal decision at the end of the day, but for me, the increased stress and time commitment of Job B doesn't seem worth $12K a year. Those kids are going to grow up quick and the afternoons home and summer time is going to be literally priceless. By the time you've finished high school, in a typical lifetime, 90+% of your time with your parents is over. So, vice versa, from a parent's point of view with the wisdom that comes with your age relative to your kids' ages, soak it on now.
If you're really hating your job, I guess take that into consideration. But if it's a matter of just not finding fulfillment in it, consider finding fulfillment elsewhere in your life rather than your work.
This. No way I would go to Job B when you lose so much time and don't make MORE money.
Think of it this way: you're trading 30 days with your kids - priceless - for 30 more days at a crappy job FOR WORSE PAY. You're going to be more stressed, more tired, and more upset, but yet you won't even make as much as you did per day at Job A. That's a lose-lose proposition.
You should value your marginal time much, much more than your current time. In other words, you work right now, but how much would it take to get you to work at Job A an extra 30 days? The answer should be: more than the rate that they pay me right now. Because that would eat up your best time, and the last of your time, so they should pay you more/you should demand more. You're going to feel that more.
I do some side work, but I only do work that (1) I like, (2) is easy, (3) is super flexible, and (4) that pays a great marginal rate. Life is too short to burn more of my good time for worse pay. So I only take on things that reward me well and/or are fun. I suggest that you do the same.
Also, you don't sound
that confident that Job B is going to land you Job C, or that Job C is going to be worth having.
Personally, I would strongly investigate Job C and/or any alternatives to Job A that aren't Job B to see what's out there. Surely these aren't the only options. If they are, I might just stick it out with Job A, or better yet, find another job that isn't as grinding as Job A but still gives you the same freedom/pay (or more freedom and more pay).
You're right to want out of Job A, given what you said, but I wouldn't jump ship without a better plan, since it sounds like you've only found something that is likely to be far MORE frustrating, especially for a few grand/year. (You could literally make that difference up - about 13k - with CC/bank bonuses/tradelines in your free time for far less stress, if you had cash on hand and were so inclined. Easier, less stressful, and why not?)