If you work close to Birmingham, take the train to Wolverhampton, you get some outstanding 'mother hill' type outcrops (especially the one at Oldbury, and also the Wrens Nest in Dudley, as well as castle hill). Also just outside Stoubridge, the Clents are an unusual outcrop (along with Whychbury with it's overgrown hillfort, spooky, and the hills towards Kinver also with another hillfort, albeit in ill repair.
Closer to Birmingham are the Lickey hills, and theres a great walk from the beakon through Waseley hills country park out to the Clents (and Kinver if you've still got the puff).
The Hills to the North of Pwelli going towards Bangor have one of Wales's most outstanding hillforts, though its a climb to get there. There's also bags of prehistoric remains in the locale.