Tier 2 (ICT) -> ILR route - Query

[santosh1983]

I have few queries regards to the my eligibility for UK Permanent Residence,

Below are the query relevant details .

Ø I am having Indian nationality, and entered the UK on 30 March 2010 on Tier2 (ICT- Inter Company Transfer) VISA.
Ø I am here from 2010 till date. My recent Tier2 ICT VISA got renewed in this March 2014 and valid till April – 2016.
Ø I used to travel India for Vacation but nor more than 30 days in each year excluding 2014 (not being to India this year).
Ø My India Vacation travel details,

31 March 2015 - 31 Nov 2014 = 0 days
31 March 2014 - 31 March 2013 = 36 days
31 March 2013 - 31 March 2012 = 26 days
31 March 2012 - 31 March 2011 = 26 days
31 March 2011 - 31 March 2010 = 26 days

My queries,

1) How early I can apply for UK Permanent Residence? As I entered UK on 30 March 2010, so on which date I am eligible to apply?
2) How early I can go for Life in UK test?
3) What are the supporting document required? Can I start gathering those documents from Next Month?
4) I may need to Travel to India for some business reason as well as on vacation from Mid-Dec 2014 till Mid Feb 2015. So I will be out for almost 60 days. During this period I will be paid in India Salary. Is this OK, to file an application for UK permanent residency in 2015.

I would appreciate your help to answer my queries.