I like the EDB > KGX > CDF^» (Cardiff - next trains) option....
How much time should I leave between sked. arrival @ King's Cross and departure @ PAD^» (Paddington (London) - next trains)?

Would probably take the train that leaves EDB @ 1130 sked to arrive in KGX @ 1551.
We'd probably taxi to PAD.

Thanks all for the excellent info!
I had looked @ EDB > CDF^» (Cardiff - next trains) via CRE^» (Crewe - next trains) but ruled it out because of a tight connection (arrival CRE 1558 & departure 1608)...
That seemed a little tough with luggage, platform change, and possibility of a delay on EDB > CRE...but if I look at it
as 2 separate tickets there are other, less arduous, options to CDF...just no 1st class....So:
1. is Arriva economy as hated as XC^▸ (Cross Country Trains (franchise)) economy?
2. is the Virgin 1251 from EDB > CRE the beloved Pandalino that's been mentioned?
I did look at the flight option (thanks for that) but we probably can't make the 1120 flight...we are disembarking from a sailing ship in Dundee and they said they can get us to the airport @ 1045....a bit tight for my liking...and the next flight is much later.  EasyJet flies from EDI to BRS^▸ (Business Rates Supplement) (Bristol) but similar timing...can't make the morning and the next flight is much later in the day...would rather spend my down time on a pleasant train than an airport

Hello from the USA...my first post on this forum.
This thread was quite interesting to me because in August my wife and I need to train from Edinburgh to Cardiff (preferred) or Bristol.  Crosscountry has a route with zero changes leaving at 1306 and arriving in Bristol @ 1943...when I use the XC^▸ (Cross Country Trains (franchise)) website to start the booking process up to the point of being able to see seats...that service appears to be the hated Voyager and not a HST^▸ (High Speed Train) as least according to the seat maps I found at:
http://help.thetrainline.com/app/answers/detail/a_id/4234/~/cross-country-seating-maps
I have seen very few positive posts about the Voyager...
So my question is: how can I see which rolling stock is actually being used on a route without going "faking booking" every route.  And if that's not possible, what would be the suggested routing to get to Wales...Travel criteria:
Departure: Aug 12
Can't leave earlier than 1130
Will have a reasonable amount of luggage so would like to reduce changes to a minimum
1st class (the XC @ 1306 was also attractive because the advance purchase fare for 1st class was only 90 pounds)
Thanks in advance
Dan Foreman