If a green card holder wants to stay outside the US for more than 12 months, they need to apply for a re-entry permit (I-131) which is good for 2 yrs outside the US and maintains your LPR status. If the period is less than six months, there is nothing that needs to be done, but many still fill out the I-131 just in case the trip overseas is extended. The re-entry permit does not delay naturalization, what delays naturalization is time outside the US regardless of if you have a re-entry permit or not. If you are outside the US for more than six months you may be determined by USCIS to have broken continuous residency, and it will be your burden to prove otherwise. I believe there are exceptions if the spouse of a military member or a qualifying federal government job. There is no alternative to the continuous residency rules.
Good Luck!