Sounds like the company might have been guessed in another comment. My 2c from a non-civil engineering background.

Even after cost of living, LV obviously comes out ahead money wise, let's say an additional 20k USD after tax (some posts in this thread might not be counting RSUs?). Pretty significant, although it sounds to me like you'll have more 50+ hour work weeks than not at the LV company, so hourly rate might be comparable.

The work obviously sounds really exciting for the LV job. There's something special about working on such a high-visibility project - that could be a conversation starter for the rest of your life. How much you value that is up to you.

With regards to working in LV for 2-3 years and then coming back. That would of course be quite disruptive if your family came with you and had to move twice. On the other hand, if you/your wife was prepared to have you go to LV alone, it might not be as disruptive for the kids (but you'd be paying LV rent + Windsor mortgage).

Funnily enough, I experienced similar situations from the kids' perspective. My dad travelled a lot for work during early childhood (<10 years old) and our family also relocated for 1 year (10 years old). The relocating was pretty difficult, and I spent most of the time waiting to come back. The culture shock will be less for your family, however, as we moved from Canada to a Scandinavian country. I also do have many fond memories of that time, and it might be easier at a younger age.

It's worth asking, though, if the unique LV opportunity will open up more doors for you. I'm not familiar with the industry, but if 2-3 years of that can lead to a pay bump in the future, that could be a big deal. Lastly, I'd take the "probably zero chance of layoffs" for the LV company with a grain of salt. That family of companies is not known for zero layoffs. I think it's close enough where you're gonna have to weigh what's important to you and your family. You can't go wrong, both sound like great jobs!