Manchester is pretty centrally based to explore lots of interesting bits of England and Wales.
The Lakes are very pretty, loads of interesting blokes-type museums (engineering based, cars, steam etc) nearby (I really enjoyed a day at the Donnington Park museum, less than two hours from Manchester <
link>), there are some gorgeous driving roads in Wales. Joining the National Trust is worth doing as planning a lunchtime stop in a NT property is a lot more pleasant than any motorway service h3ll-hole. Make a few visits and you've justified the joining fee.
Get busy on Google, plan a few routes and burn some petrol.