Touring - Cardiff to Gloucester: Local Knowledge please!

I'm planning the Sustrans Severn and Thames Cycle route this October. Zoom Airlines can get me into Cardiff, Wales. My map shows it to be much closer to Gloucester than Gatwick.

Does anyone out there have some local knowledge about the Cardiff airport? Can I easily take a train to Gloucester? Is it possible to bike?

There may be a cycle route, but the roads in this region are fast and busy. I wouldnt attempt it.
There is a train from Cardiff to Gloucester, just over 1hr.
http://www.nationalrail.co.uk/
BarryTown is the nearest station, but only ride there in daylight.
http://www.multimap.com/map/browse.cgi?client=public&X=305000&Y=165000&width=500&height=300&gride=&gridn=&srec=0&coordsys=gb&db=&addr1=&addr2=&addr3=&pc=&advanced=&local=&localinfosel=&kw=&inmap=&table=&ovtype=&zm=0&scale=100000&right.x=3&right.y=99

Confusingly, each train company has a different bicycle policy. The Cardiff-Glouc route is run by Wessex Trains. Their bike policy is pretty good, and other info is avaliable...
http://www.wessextrains.co.uk/helpingyou/index.php?subnavID=210

Unless you are staying in Gloucester, it is usually easier to use your bike from a smaller town or village station. You don't have the problems of navigation and traffic.

Michael, you truly are an angel, and a font of local knowledge.

Here's the bottom line:
Am I better off to take a direct flight to Gatwick, hop on the train (there is a proper station there) and go directly to Gloucester or should I fly to Cardiff and make train connections from there to Gloucester?

Gatwick seems to have the advantage of a train station right in the airport. It will be a red-eye (overnight) flight from Canada. I'm arriving about 8:00 should be ready to move out of the airport around 9:30. It will be a weekday.

If I go to Reading first, I can arrive in Gloucester in the afternoon, just in time to take a B&B and start out fresh the next morning. Your advice is appreciated.

By the way, didn't you tour down to southern Europe last winter? Do you have a blog?

Tricky call.
From Cardiff, you probably have a 1hr ride (5miles+getting lost), then 2 hrs+ of rail to Gloucester.
I dont think you will be in any condition to ride a bike on the wrong side of the road after a read-eye flight. It usually takes me 30-45 mins to get my bike roadworthy again after a flight. With rail travel, you just need to have it "roll-worthy" and can fix it up on the train.
A warning though, Gatwick train terminates at London Victoria.
The Reading line leaves from Paddington Station, which is a 2 mile ride across central London .
http://www.multimap.com/map/browse.cgi?client=public&X=530000&Y=180000&width=500&height=300&gride=&gridn=&srec=0&coordsys=gb&db=&addr1=&addr2=&addr3=&pc=&advanced=&local=&localinfosel=&kw=&inmap=&table=&ovtype=&zm=0&scale=50000&left.x=6&left.y=96
From the "Tourist Info" sign, just S of Buckingam Palace, go 1/2 mile North to Hyde Park. Cross to the top of the park and head North to where you see the railway (BW line) terminate. Hyde Park is OK for cycling.
There may be a rounderbout rail link to Reading, do you know of one?

The only bit of S Europe I have toured is Slovenia in September, a lovely little country.

http://www.nationalrail.co.uk/planmyjourney/Time_Table/Matrix_Journey_Details.asp

This is the route I'll be taking:
http://cycle-n-sleep.co.uk/rinfo/map%20S&T.htm

Last spring I travelled from Gatwick station to Reading on Great Western. It was a direct link running about every hour. There was no charge for the bike, but I had to store it by the doors and you never know which side the platform will be on. I'll check out your info and report back.

Trains run approximately every hour Gatwick to Gloucester, change trains at Reading and Swindon. Journey time 3hrs to 3hrs 30mins maximum dependent on time of day. This saves you going into London and I am not sure whether you can take your bicycle on the Gatwick Express to London - could not find anything in their travel conditions.

Looking at the two situations I would fly to Gatwick rather than Cardiff.