Our girls are now 9 and 11 but we moved back to Vancouver (where my parents live), eight years ago. We had tried to make Boston and even Seattle work but with two jobs and two kids, even 3 hour drive away wasn't enough.
Was not optimal for my career but we decided it was easier for me to travel to SF while optimizing stability for the girls (also helped financially, culturally and life-ly).
This was and has been 100% right decision for us and for that phase of our lives (eg. kids were 1-10 yo)
But I would ask these questions to make sure right for you:
1. Do both sides see their role of grandparent vs. childcare the same?
Often kids (us) assume their parents will naturally fill the fill in childcare role). Many of our parents are "done raising kids" and want to just enjoy being grandparents (or their health isnt what it was to run around toddlers/lift preschoolers) - we had to work through boundaries and definitions in the early years; think of it as building a bench with different roles to be filled - full time care is very different from every Wed stay-overs which is different from "in a pinch" care. Define your needs, figure out who fills each.
Mainly: don't assume the childcare bit and make sure you have the convo with each individual grandparent/fam member.
2. What impact to work life are you willing to bear?
For me, constant travel to SF was tenable bc same time zone, quick flights but has def not been ideal. Could also make it work bc I was where my team was each week. But if you're so stressed or absent that you feel like you're not getting the time at home that you need, or if you're not feeling effective, it's not worth it. It seeps into marriage and relationship with kids.
3. How important to your family values is multi-generational community?
I was most surprised about how nice it was to feel "continuity" when having my kids meet and be with people I grew up with/their kids, esp in Indian community. The intangibles of community can sometimes offset the friction of the work side.
If you do do it, I would frame as a 1-2 year experiment. If it works, great, if it doesn't, you have a set timeframe to go back or figure next out.
Above all, I'm most proud of the relationship our girls have with their grandparents. It's something I never had and in these crazy early years, we found a way that gave them that while also freeing my husband and I to go build companies.
Happy to share more details as we've the nuances for years.