There is a lot of info on the web.
If you file your tax return you should not have a problem. Tax free only after 321 days out of country and only up to US$80K...at least that is what it used to be.
I used to work overseas while on a green card and traveled home on my time off. Every time I entered, the usual questions...how long were you gone (they know) and who do you work for. Never had a problem. Got a US passport now and that is a lot easier
Good luck!
Work Abroad, Live Abroad - Immigrants: Don’t Treat your Green Card like it was a Visitor’s Visa
U.S. Citizens and Resident Aliens Abroad