There was accomodation on Llanbadarn, but it was closed a year or so ago now, so all accomodation is on the main campus/in town/seafront.
I think it was because it needed alot of work to be renovated, and also the university had loads of empty spaces in accomodation on the main campus until this year. It's within walking distance of the main campus/or not long by car/bus though - you can get a card for £30 for free bus travel within Aber for the whole year.
I always thought the Llanbadarn halls were a bit out the way of the main campus, but obviously were more useful if your lectures were all there!
No more than 20ish mins, i think, i've only ever driven past it, but it's not too far away. I know people who cycle to/from there and it doesn't take them too long As others have said, though, there's a regular bus that stops right outside the entrance