D..
Tax help. That's pretty important. You need to know how paying taxes will work, including if you'll need tax equalization. You definitely need someone to do your taxes for you and that should be a perk from your company.
Security costs should be offered. A security system in your home, that kind of thing. They should offer medical insurance as well.
Would you have an expat package or a local package? That's pretty important. You should have the package in writing before accepting the position. However, they usually will not show you a package until you two are very close to coming to terms on the job. The written package normally comes WITH the offer. I would not accept a job without reading the package fully. However, you can't expect them to give you the package to read unless they are going to make you the offer.
The point is, I think that you'll have to do all the work anyway just to come to this point.
If you know anyone with any US company who lives and works there, you should call them up and get them to talk about nuts and bolts. On the ground info from people who live and work in the place you would be is your best way of figuring out if it's for you.
Good luck!
Dawn