If you have a collection of GPX files for walks, and you are happy the make them public, it is easy to create a page to do that (for an example, see https://www.derbyramblers.org.uk/routes/map-of-walking-routes.html):

• Create a folder on the website to hold them all. This must be a sub-folder of "images".
• Upload as many gpx files into the folder as you want
• From the back-end of the website, create a new menu entry of type RA Tools > GPX Utilities,
• From the "Options" tab,  select "Display a library of Routes" and specify the folderholding the files
• Specify whether or not you want to allow a visitor to the website to be able to download the routes

Thats all! From the front end of the website, the menu entry will now show the whole collection of Routes, with details of distance etc. Clicking on any of them will show the route plotted on a map. Initially, the Routes will be shown in ascending order, sorted by their title. However, to search for walks of a particular length, there is a drop-down list at the top of the page from which you can choose different options: