Heyhosilverballs - I live in a community like that in the midwest, in a suburb of a city with a shocking murder rate. I often don't lock my door or my car, and the generosity and community spirit is fantastic. When there are marches to support liberal causes, hundreds of people decamp to the trains downtown from here, with banners, babies on shoulders, etc. You really don't see that side much on TV, understandably I suppose.
I experienced the downside of the Hague Convention myself, having divorced with five DCs. The upside to staying here is that my DCs were able to stay in their terrific high school district and so far have gone to great universities. Fingers crossed they will all be financially independent upon graduation (two more to go in full time education). The downside is that my extended family are all in Ireland, UK, and continental Europe, and flights are expensive. Plus, once the DCs started high school and had activities like summer school, sports camps and summer jobs it was very hard to get them all on a place to visit their rellies across the pond.
I don't think it's at all unreasonable to consider whether you want to be stuck in the US until your younger child turns 18, or whether you would then find yourself stuck between a rock and a hard place because your children's lives would be firmly rooted in the US, with the prospect of them starting families of their own ahead of you. If you move back at that point, can you really just take up your old life where you left off? How do you maintain the sort of sustained contact that makes family life a reality if you are on one continent and grandchildren are on another? Otoh, how do you do your share of caring for aging parents at such a remove? How would your children do that for you if they were in the US and you were back in the UK?
Best to treat this as a permanent break with the UK and not to entertain the hope of returning and life getting back to where it was. How does that sound as an option for you?
If you are still inclined to go, is it possible for you to enter into an agreement with your H that would be binding that the DCs and you would be able to return to live permanently in the UK in the event of divorce?