I went to Paris by plane, and Dublin by ferry. The plane tickets from Manchester Airport were cheaper and faster than equivalent trains to Paris. On my way to Dublin, I took a train down to Holyhead in Wales, and a 2 hour ferry trip across the Irish Sea. The ferry was basically a giant floating mall. UniTravel is not good for booking accomodations.
Youth hostels are cheap, but of variable quality.
Buses and taxis can be caught at the University Underpass, which is beneath Alexandra square. The bus service is alright, although the double-decker buses sway alarmingly going around corners. The number 1 takes you straight into Lancaster. Any number 2 bus will get you there as well, by a rather more round-about route. If you can, go with a friend, as this makes the trip more enjoyable.