Google maps reckons [url= http://maps.google.co.uk/maps?f=d&source=s_d&saddr=LS12+2TU&daddr=Llangennith,+Swansea,+West+Glamorgan+SA3+1HS,+UK&hl=en&geocode=%3BCW_lQ4Bh_fr0FdxXEwMd70C__ylVSdf-tpRuSDEocCYb31ENfQ&mra=ls&sll=51.599324,-4.243217&sspn=0.00913,0.016544&g=SA3+1HS&ie=UTF8&z=7 ]motorways via Birmingham[/url], but as we're leaving Leeds at 3.30pm I reckon we'll be hitting traffic on the motorways so inclined to [url= http://maps.google.co.uk/maps?f=d&source=s_d&saddr=LS12+2TU&daddr=53.304621,-2.697144+to:Llangennith,+Swansea,+West+Glamorgan+SA3+1HS,+UK&hl=en&geocode=FXXtNAMdIOLn_ymhYquvx155SDEsxBQmT7L-sw%3B%3BFdxXEwMd70C__ylVSdf-tpRuSDEocCYb31ENfQ&mra=dpe&mrcr=0&mrsp=1&sz=8&via=1&sll=52.546296,-3.383789&sspn=2.288265,4.235229&ie=UTF8&z=8 ]go cross country[/url].. What does the oracle that is STW think?
Cheers!
Came past the roadworks at Newport/Cardiff yesterday afternoon and they were a pain. Cross Country looks more fun - go that way, even if it takes a little longer.
Rachel
You'll be hitting the traffic on the cross country routes, too.
I'd just load the car with CDs and junk food and choose a route - from Leeds I'd prob go M1 then M42 round the south of Birm, M5, M50, M4 to Swansea.
M1 J28
A38 Litchfield A5 Tamworth
M42
M5
M50
then last bit across the top to bypass Newport/Cardiff roadworks, Swansea etc and pick up end of M4 past Neath
A48 Carmarthen
Yes you will hit Brum around rushhour but the variable traffic management on the M42 it generally flows okay these days and unfortunately unless you go down M1 all the way to M69 then M40 (J21 can be bad) there isnt an easy way to avoid it
Personally I find A38 traffic better than A42 but it depends what time you would hit the three roundabouts at Derby (its also a bit longer)
Cheers all.
Ummm...in a roughly southwest direction 
I'm surprised the time difference between the motorway route and the twiddly-little-single-carriageway-roads-through-Wales route is so little; even on a slow motorway the chances are you'll still be averaging more than a good clear run (which you won't get!) through mid-Wales.