We are flying into London end of May, 2016. Spending ~4 days sightseeing in town, after which we want to see some sights outside of London. We are interested in seeing: Brighton, Salisbury Cathedral; Stonehenge; Bath, Oxford, Warwick Castle & Cambridge. (not sure if Oxford and Cambridge would be redundant?) On a map, it sort of looks like a big circle around the perimeter of London. I think we would prefer NOT TO drive (other side of the street, etc.) so I am wondering if we can do mass transit to get from one place to the next, or should we stay in London and take tours out and back each day? Or some combination? We will probably have 6 days to do this.