I usually have to decide before I go wether I'm going North (York, Newcastle, Edinburgh, Scottish Highlands and Islands) or South (London, Cambridge, Bath, the Cotswolds, Wales).
All of the things you enjoy can be found there, and it's so small*, you can do all of them within a couple hours easy train travel. I usually have to decide before I go wether I'm going North (York, Newcastle, Edinburgh, Scottish Highlands and Islands) or South (London, Cambridge, Bath, the Cotswolds, Wales). That keeps the travel reasonable and allows me a few days in each place. Autumn weather is milder than you'll find back home, though, yanno, occasionally wet.