I am in same boat.
Maintain a residence in the USA. Enter the USA each 6 months or your resident status can be re-evaluated. (They can pull the green card).
It is all about intent. If you can show that you desire to return to the USA full time and settle you will be ok. That can be done by owning a house, maintaining a residence, having family inside the USA, bank accounts, loans etc.
Remember to enter each 6 months.
Your absences will reset the 3 or 5 year clock to getting citizenship.
The laws governing Taxes and Immigration are from completely different books. The 35 days for taxes has nothing to do with your green card.