Here are links to on-line ‘libraries’ of walks and rides:
Go 4 a Walk: https://www.go4awalk.com
More than 13,000 walk route maps in the UK, all free to download.
Transport for London has a Walk London section on its website. Beautiful and interesting walks can be found all across central and Greater London.
Countryside Walks – details and maps for more than 1,800 walks, many of which are in sites managed for wildlife and environmental benefit.
The Walking Britain website has walking routes to download for free, searchable by county, etc.
Walks led by The Ramblers’ Association volunteers (all fully trained).
The Outdoor Guide (includes a walks finder).
Ordnance Survey ‘Get Outside’.
Ordnance Survey ‘Get Outside’ app.
Where2Walk provides free downloadable walking routes for the Lake District, Yorkshire Dales and North York Moors.
Let’s Ride: https://www.letsride.co.uk/routes.
Cycle routes that are free to download (search by postcode).
Cycling UK‘s 140 routes.