I released a Route Builder tool just a few minutes ago ( Updates on February 15, 2021 ) which includes the ability to download your Routes as GPX files.
I have absolutely no idea if I’ve built this correctly, or if there’s anything else I can include to make the files more useful. Please let me know here. 
When selecting the Download GPX button, it opens XML file in a new tab (at least Chrome does) vs triggering automatic download. Needed to right click button and ‘save as’ to get file saved locally.
My limited understanding of GPX files are they are a type of XML file so I was able to import the XML file into one platform’s GPX viewer but it failed in another visualizer. I could be choosing non-ideal platforms to test with but those are the first two I thought of. Since the file comes out with an .xml file extension, some platforms may reject it because it doesn’t have .gpx extension.
If anyone has a fancy watch that can import & display maps, would be good to know if the XML file works there.
Thanks!! This was all very helpful info, especially those viewer links.
As of Updates on February 16, 2021 the GPX downloader should work properly. It’ll actually download a file, with a .gpx extension, that can be loaded into those viewers.
Let me know if there’s anything I missed, or any info that could be included/corrected in the GPX file that’ll make it better.
Found another item. When downloading gpx file, the file name is “CityStrides-Route-##”. If there is a custom name saved, probably should be that name. Ex: If I create a route and save it as “Monday run” in CS, I’d expect the export file is ‘Monday Run.gpx’. You may need to do some character restrictions on name field then for internationalization purposes and OS limitations.
If no custom name, then the current behavior would probably be ok. Don’t think most users would know the number in file name is route number in CS db. It’s a better name for file than the UTC timestamp though.
Ooh, thanks! 
I’ve fixed that in the exact way you described: use the custom name if it exists, otherwise use the date. I kind of co-opted some code that was meant to clean up text for another reason, but I think it’ll be suitable here as well (it’ll just be a little more aggressive than file systems actually need).