I was a US citizen working in China. It was very complicated. I ended asking my CPA who has many US clients in China. I would suggest you do the same. In general:
* If you are not in a foreign country for a whole calendar year, probably only foreign tax credit is applicable. Note that there is a SEPARATE foreign tax credit alternate minimum tax.
* If your spouse remains a resident of a US state, you probably still need to pay state tax.
* Note that even if you reside in a foreign country for a whole year, housing and transportation allowances may still be taxable.
* You need to keep track of the travel for the entire year down to the dates.
* I believe foreign residence means < 30 days in US (you may want to take a tax home test to see if you can qualify for bona fide presence or physical presence), counting from the departure from a foreign country to arrival (not arrival in US to departure).
* As you will have a foreign financial account, you may have to file FBAR. If you have some ownership of a foreign company, you may have to file Form 5471, I file both every year.