Great Western Coffee Shop

I need to travel from Cambridge (or Waterbeach) to Cardiff on the 23rd March to arrive before 2pm.  Can travel back anytime the next day.  I don't want to drive to Cardiff as my destination is right on top of Central Station and there's nowhere to park at my hotel.

Then need to travel to Portsmouth and be there Saturday 25th and Sunday 26th.  But this is the complicated part: I need my car whilst there.  I can arrive Friday or Saturday, it doesn't matter.

It seems a little pointless to travel up to Cambridge (from London) on Friday afternoon, only to travel back past London the next morning.  So I'm thinking of driving to West London somewhere to park, travelling to Cardiff from Paddington.  The train fare is only about £2.50 cheaper each way.  Then I can drive straight onto Portsmouth.  But I've no idea where to park in West London without spending an absolute fortune.  I previously lived near West Ruislip and know there's on-street parking, but it was almost impossible to park there after 9am.

Any suggestions would be helpful.  I'm trying to plan quite a few trips at the moment, so I'm going a little mad and not seeing obvious solutions to logistical problems!

I'd tend to look at parking at Dickdot.   

Car: Cambridge - St Neot's, Milton Keynes, Buckingham, Biceste, Oxford Ring, Didcot.
Train Didcot to Cardiff and back
Car: Didcot - Winchester - Eatleigh - Portsmouth

Same in reverse, except for the train trip.

Avoids fighting in and out of London at all.

Well I truly spilt my coffee when I read that Grahame......... :P

Hmm. Used to be a train on that route via Bedford!


Hmm. and that one via Newbury and Shawford Junction!

Thanks for the Didcot suggest, Graham.

In the end, I booked Cosham (that'll bring back memories) to Cardiff Central, so I'll just come down to Portsmouth a bit earlier than planned.  Only £8.90 each way, so beat any fares from London.  Plus I know where to park for free nearby.