Hi all i am in a situation.Currently in F1 status after completing undergrad and planing to marry my girlfriend who is permanent resident and will qualify to apply citizenship on feb'16. How should i plan regarding immigration issue. If we get married now how will process start and do i have to be in status after getting married.? how long will be the process?

If you marry a permanent resident, USCIS will take 2 years to process your paperwork (the last I checked; look at the new priority date on the latest visa bulletin). You will have to maintain your status until then.

As far as I know, there is no wait for US citizen (may take 6 months for the paperwork to process...double-check this). 

We are not on same state. She is in different state, its expensive for me to join masters in that state.Can i join masters in other states?

From what I've heard, it's better to stay together in the same address when applying for GC through US citizen, gives credibility to your marriage as something genuine and not spurious. I could be wrong.

There is no right answer to your question. Of course it is better to stay at the same house and show you have joint bank accounts/utilities account etc to prove the legitimacy of your marriage. However, the most important thing is that you have to be able to prove to the USCIS official during your interview that the marriage is legitimate. There is no set way to do it. If she is Nepali, it might be easier for your to convince him even if you are living in different States. Type out your love story (i.e. how you met, where you met, when you decided to get married, why you are living in different states etc) and read the story back to yourself. Does it sound reasonable? You will know your answer. If you want a second opinion, send me a PM.