Please help me to understand N900 Central

Can I access my files without internet? i.e from laptop/ipad/tablets connected to the router (like go flex). if so how?

Is it also posible with N900 HD (with usb hard drives).

I want setup this router in place of WNDR3700 to stream my media to tablets and laptops. I am tired of copying files multiple times. Also my nexus 7 doesn’t have MSD.

WNDR3700 has dln server, but it never worked right. I can not pause, resume… media server will not respond until reboot.

I understand I can access files remotely, that is a plus but not a must. I can use 15 gb google drive and 25gb box for that.

Hi, yes, you should be able to access the MyNet from most devices connected to your local network without the need of internet. From your Android/iOS device, you can use the WD2Go app for remote and local access. For the steps to access the MyNet from your PC check page 65 of the manual. 

Manual

http://www.wdc.com/wdproducts/library/UM/ENG/4779-705074.pdf#page=68