This is just a thought but since you have good total time, Part 121 experience and 1500 total PIC the Part 91 job might allow you to have the option of going to an airline as well as making contacts in the Part 91 world and maybe finding a good corporate position. You didn't say why you left the airlines (or flying altogether) but you will need to explain that. If the answer is your company went out of business or you got furloughed there is obviously no problem. The answer to your question is a tough one, I'm not sure there is a right answer. Good luck with whatever you choose to do, I'm sorry some people here had to take your thread and turn it into another Delta Vs. SW argument.
You're right that this GA opportunity could open other doors, but moving on to a larger airline where it's less of a flight and more of a voyage (which is what I thought about my first DH to MCO from CVG on a 767 as a new FO a million years ago...and yes, it is a bit hokey) has always been the goal.
I took my airline's buy-out some time ago to spend time with my family before returning to the industry (or so I hope). I'm not sure how that will be viewed, but if negatively, that's ok...having that quality time with family was the most important.