So many places so little time

Ok heres the deal. Starting holiday from Stratford upon Avon after husband finishes work in Birmingham on October 25th. Staying three nights in Stratford upon Avon to see the Cotswolds, Shakespeares house and gardens and the town, then train to Bath (3 nights) to explore town, Castle combe and Avebury.
Now this is where I get stuck, dont know if it would be too rushed to go to Cardiff for a couple of days, Caerphilly castle then up to Aberystwyth before heading back to London or heading back toward London.
Was thinking of probably training it the first part, then maybe driving from Cardiff or Bath.
Have to be back in London night of Thursday November 5th to fly out of Heathrow the next morning.
Any recommendations greatly appreciated.