If you are going straight from London to Telford, you might want to consider going by train - providing they are not on strike! The fastest journey time from London (Euston) to Telford is 2 hours on the occasional Virgin direct service. (On most options, you will have to change). A cheaper route is to use Chiltern Trains from London (Marylebone) to Birmingham (Moor Street) and then walk to New Street Station for the journey to Telford for which it is best to purchase a separate ticket (£10.20 return). That would give you a chance to see some fine Victorian buildings in Birmingham city centre.
www.nationalrail.co.uk
For longer journeys - it is cheaper to pre - book train travel. http://www.chilternrailways.co.uk
www.virgintrains.co.uk
http://www.arrivatrainswales.co.uk
http://www.londonmidland.com
If you are going to drive, going via the M1/M6/M54 will take you through some congested areas skirting Birmingham. (Look at it on Google Earth). You could make more of a 'holiday' out of your trip by taking the M40 out of London to visit Oxford first. (Though, you might wish to take the train & having walked around Oxford centre - then pick up a hire car). Just NW of Oxford, at Woodstock, is Blenheim Palace.http://www.blenheimpalace.com
From where, you could continue driving NW to Stratford-upon-Avon.http://www.visitstratforduponavon.co.uk (I would suggest that you would now need to stay 1 night).
From Stratford, I would be inclined to avoid the Birmingham area and take the A46/A422 towards Worcester & then the A449 to Kidderminster and A442 to Bridgenorth & Telford / Ironbridge.http://www.ironbridge.org.uk
http://www.svr.co.uk
Shrewsbury is worth a visit but the Castle is not up to much. http://www.visitshrewsbury.co.uk
Another Shropshire town that you might wish to visit is Ludlow http://www.ludlow.org.uk Just north of Ludlow (on route A49) is this place:>http://www.english-heritage.org.uk/visit/places/stokesay-castle/
Shrewsbury / Ludlow are on the border with Wales. If you have time, it is well worth extending your trip westward into Wales. If so, Powis Castle is well worth a visit (at Welshpool).http://www.nationaltrust.org.uk/powis-castle/
The part of Wales around Dolgellau is VERY SCENIC. On the west coast - reached via Barmouth - is Harlech Castlehttp://cadw.gov.wales/daysout/harlechcastle/?lang=en A little further is Portmeirion.http://www.portmeirion-village.com/visit/
Finally, if you want to go down a real (disused) coal mine, I suggest you drive to Big Pit at Blaenavon - in south east Wales. (This is about 2 hours driving time from the Telford area). http://www.museumwales.ac.uk/bigpit/ (This could be combined with the Brecon Beacons National Park). http://www.breconbeacons.org
www.visitwales.co.uk
www.visitengland.com