It's a tough decision that can hardly be done in a few text posts, but as an outside reader, these two things you said stood out to me:
"- increased take home pay of approx $50k over 12 months
- better & more fun work environment than the regular job"
If those were the only factors, I would do it. Heck, you may get back to your old job and decide in a year to move on to another job anyway, and then you will have missed out on the above two things. Surely, your main concern is what happens AFTER the year is up, so you'll have to think carefully about an exit strategy, but you can always use the 50k to buy you some time... :)
Good luck!