I have a similar memory. Used to live in Freshbrook when I was a teenager and, for a while during holidays, I had a job working in the kiosk at Coate Water. The cycle path from Toothill to Old Town was brilliant. I used to be able to get home on my bike in less than 20 mins with a following wind.
It's a shame to think that the countryside along side the path is being built on...but people have to live somewhere, I suppose. Strange to think that during our lifetimes we can all think of parts of Swindon that used to border countryside that are now completely surrounded by other suburbs/areas. How many folks in Greenmeadow, for example, are now regretting the fact that the countryside is 30 mins further away than it used to be?
I am not from Swindon, but do remember as a child when we used to come to Swindon that it was all countryside until we reached the Running Horse pub - the pre "west Swindon" days.