Crowdsource: How should she make the decision about moving to be closer to her kids' dad?

Anon is looking for a little group wisdom. Her ex-husband lives four hours away from her and their children. She's considering moving to the city he lives in, but would like some input on things to consider while she makes this decision so she's not missing anything. She's looking for decisions-making process help, not straight up "move" or "don't move" advice.

Things to consider:

She lives in a mid-sized city and he lives in a big city.

She's underemployed in her current city and would likely be in the big city, too.

He's fully employed in the big city.

Her mother lives with her now and helps her with the children, but wouldn't move to the big city with them.

He will be involved with the kids if they are in the same city (and is as involved as possible currently from four hours away).

 

Thoughts? I feel like my own personal situation is coloring my answer, but the things I'd think about:

1. The kids. Obviously it is better for them to have more and more easy access to their dad. But if being closer to their dad puts their mother in a situation in which she can't survive/thrive financial and emotionally, that isn't a positive for the kids.

2. Support (physical and emotional). Right now she has her mother, who is doing both kinds of support. Will the kids' dad be able to step in for the physical support, and will she be able to find emotional support in the new city?

3. Stability. Being underemployed puts a twist in it. She could have better prospects in the big city, but the cost of living is likely to be higher there, too. It could come out a wash, or she could end up trading down by moving.

 

Can anyone think of things I'm missing that Anon should consider?