So much I could say, but all I will say is that if you feel called to serve God overseas, I doubt you will find a better set up that will let you do so and still be a significant part of your sons' lives. You haven't mentioned how often you get to see the boys now, but Skype is great and if you are being offered the chance to Skype daily then it sounds like your receiving organization will place a pretty high value on your family. Add to that the fact that you make it sound like your boys think this is the coolest thing ever, and though it will be tough at times I think you should go for it. Barring any major upsets in your visit that is.
If you get a chance during your visit try to meet with other families who are foreigners there to ask about things like what they were told would happen vs what actually happened (this can be a huge discrepancy especially in cultures where they always tell you what they think you want to hear), schooling options for your child, what you should stock up on and bring with you because you can't easily buy it there, etc.
As far as the overseas thing, living in Haiti or living two states away ends up being really about the same in terms of the impact on the time you will spend in person with your sons. If anything, living overseas means that when you do come home everyone makes it a point to see each other because they can't do it easily just anytime they feel like it.
One last thing about being called and family, it sounds like you have probably done this already, but the call and the sacrifices are something the whole family shares. Your wife and children need to have their voices heard and be behind this decision. Also if you do end up living abroad pay special attention to your wife getting her social needs met. It is very easy for women with small children who are living abroad to become extremely isolated and lonely while the men are so wrapped up in ministry activities they're never around, so here's a heads up to keep an eye out for that kind of attack on your family as well, wherever you end up.
If you get a chance during your visit try to meet with other families who are foreigners there to ask about things like what they were told would happen vs what actually happened (this can be a huge discrepancy especially in cultures where they always tell you what they think you want to hear), schooling options for your child, what you should stock up on and bring with you because you can't easily buy it there, etc.
As far as the overseas thing, living in Haiti or living two states away ends up being really about the same in terms of the impact on the time you will spend in person with your sons. If anything, living overseas means that when you do come home everyone makes it a point to see each other because they can't do it easily just anytime they feel like it.
One last thing about being called and family, it sounds like you have probably done this already, but the call and the sacrifices are something the whole family shares. Your wife and children need to have their voices heard and be behind this decision. Also if you do end up living abroad pay special attention to your wife getting her social needs met. It is very easy for women with small children who are living abroad to become extremely isolated and lonely while the men are so wrapped up in ministry activities they're never around, so here's a heads up to keep an eye out for that kind of attack on your family as well, wherever you end up.