GC for Parents - Consular processing in India vs being in US

[windy77]

Hi, I am US citizen have question related to applying GC for my parents in India. a) Should i file I-130 petition for them being in India, or b) wait for them to come to US first and then file I-130 form along with I-485 together. I have few questions to know which direction i should take (a or b), which is better option ?
1. How long it takes for cases a and b ?
2. which is more easy a or b ?
3. what is the success rate for a and b ?
4. Can my parents travel between India and US when a or b is in progress ?