Depending on the player, TV etc they may not play if you copy in the DVD format, you really need to convert them to AVI, Mp4, DivX etc that sort of format for them to be recognised, a DVD will require from 4 to 7gb of drive space where the other formats a lot less.
It is doable to put a DVD onto a USB stick, you will need a pirate programme like DVD Shrink or DVD Decrypter or similar (so I have been told ) they also need Nero to help compile the files.......this sort of programme will crack the lock code and allow you to copy the disc, it will also compact the data so it will fit onto a blank DVD or you can just put it on a HDD, once that is done you can convert the DVD file to a more compact format like DivX, AVI etc.......just have to make sure you don't compress the files too much or the quality suffers big time, keeping them to about 1.8Gb usually allows for a good pic and sound........................
It can take bloody ages and it isn't really legal, so my informed sources tell me...............