maintaining continuous residence, live out of US family/medical reason for 18 month

[sapper]

Hello,

I have few questions about maintaining "continuous residence" status for applying for citizenship later.

I received Green Card in April 2007,
I have been living in USA since then continuously and employed here.
I would like to go to India from this June 2010 for almost 18 months years for family/medical reason.
(medical reason is : I am diabetic, planning to take different type of treatment in India.. I am not sure
whether to mention this reason to Immigration, does this help my case or creates issue)
Is there anyway I stay outside USA and become eligible for citizenship in 2012 April.(that is 5 years from 2007)
I can not take job transfer, I have to quit the job here in USA and take a new job in India.
I read the USCIS naturalization requirements. I am willing to come to US once in every 6 months for a week or two for period of 18 months .

Will that be enough for citizenship?
Will I face any issue during my entry into US at port(by immigration officer)?
Do I need to apply for Re-entry permit?
If I apply for re-entry permit and travel to US once in every 6 months? what will happen to re-entry permit?
Other than job transfer is there anyway I can apply for N-470 ?

Few other points:
1. I don't own property in USA
2. I will file tax and maintain USA address by giving friend's address
3. I will maintain US bank account and credit card

Please help me by suggesting what should be the better way.

Thanks.

[Ron Gotcher]

As long as you document it, you shouldn't have any problems. That is a legitimate, temporary reason for living abroad.

[sapper]

Thanks Ron for the reply.
What type of documents I will require?
do I need to apply for re-entry permit? if yes can I specify the same medical reason in re-entry permit?
I guess still I need come to US in once in 6 months?
while I am in India to support myself and family I will be taking job in India.. will that be an issue?

[Ron Gotcher]

File the basic form (I-131) with a letter that explains why you need to go abroad and remain for a temporary, but lengthy time. Attach whatever evidence you have that substantiates your claim.