The Sustrans website will tell you all about the National Cycle Network in the UK which “is a series of traffic-free paths and quiet, on-road cycling and walking routes, that connect to every major town and city. The Network passes within a mile of half of all UK homes and stretches over 14,000 miles across the UK.”
They also have a shop where you can buy maps, books, clothes and accessories etc, although you might have a good cycle shop in your own neighbourhood where you can get everything you need; or, even better, check out the second hand shops and the shops of animal-friendly charities and re-use something someone else doesn’t need any more (for a fraction of the price).