Thank you very much for the advice. Apologies for not replying sooner, I guess one downside, if there ever was any, to booking a flight at such late notice is that there is so little time to prepare!
I have in the end, with the advice here and from others to just keep it simple. 3/2.5/3/1 split of Dallas/Houston/Austin/Dallas (fly out day). I get a couple of ball games in which I'm really looking forward to.
I admit I had no idea about coach travel in the US - have used extensively through Europe for shorter trips. Thank you for that advice - I have gone for a mix of Greyhound and Megabus. The prices were quite acceptable, getting to Austin was pricey - but it's MotoGP weekend at COTA so that probably has something to do with it.
Accommodation wise it is Airbnb, affordable enough at the last minute. I appreciate the comments re Houston but since I'm in Texas, I wanted to get there and see it, that way if the city is nothing special I will not have to venture down that way again
. Particularly for a day at the Space Center, which leaves me a full day to explore some museums and the city in general.
On the way to the airport, finally, I am going to the US
....fire up the BBQ haha.
Thanks again