OK, since you didn’t like my advice, here’s some completely different advice :).
Don’t worry, I’m (mostly) kidding - I don’t feel you were brushing me off and I’m certainly not offended. But, it kind of seems like you’re looking for reasons to make the move and ways to dismiss the reasons to stay put. Which is fine - perhaps that tells you which way your heart is telling you to go?
As a father of 2 young kids who are lucky to have four grandparents who love being involved, but also keep a respectful distance, I totally get what you say about your kids and grandkids, looks like you have the right mindset, good for you. No, your lives should not be defined by theirs, of course. Obvious point is obvious, but don’t mention to any of your kids about their proximity to the old/new locations and how this factors into your decision. But it might be worth mentioning to the daughter who is nearby how a possible opportunity has come up that happens to be near your son, and see how she reacts. Maybe she relies on you more than you realise? Even the most well-adjusted and supported kid might feel a little abandoned, even when they have a little family of their own.
All that said, I think both sides of the location thing are not the main factor. It seems to me the fear of being in a job you don’t really enjoy for the next 7 years is much more important. And that is totally understandable - it’s the biggest single activity occupying your waking hours, after all. As you have already said, you can always try living in another part of the country when you retire, many people do. So I would cross that off my pros and cons list if I were you. My biggest concern now is your statement in the OP that neither new job would necessarily be terribly fulfilling, just an improvement over your current one. This indicates to me that if you change roles, after 6-12 months you might well find there are aspects to the new job that, while perhaps not as bad as what you moved from, are becoming rather tiresome. In other words, are the new jobs enough of an improvement to justify the upheaval (like you say, moving sucks, I hate it)? You don’t know, of course. But I have a feeling the job opportunity far away is an excuse to move to a new state, when really it should be the other way round. In other words, if the question was “I have a great new job opportunity but I’m worried about moving to another state, should I go for it?” the answer would almost certainly be “yes”, but here it’s “I’d really like to try living in another state and I’ve found a job that would probably justify that”, in which case the answer might be to just wait until retirement and do it then.
If all else fails, you could always try the old trick of designating one option “heads” and the other option “tails”, then flipping a coin - your satisfaction (or lack of) with the result then telling you how you really feel.
Spending days trying to pry information out of dishonest, uncooperative, unintelligent people, seems to have undesirable effects on my social interaction outside of work.