I'll start with the least important detail but the first one I noticed: the main page features an example image that shows mountains scenery that could have been the foothill of the divide from the south west (based on the combination of the vegetation and peaks), however, the trip planning details are for somewhere in Norway which was very confusing until I checked and saw it was an AI generated image.
But to the more important stuff: the main tools I've been using for trail/route planning (for over 6K miles) are Gaia and CalTopo. These tools have a lot of route building tools and overlays for both planning and navigation and I guess you don't want to replace these tools and if you acknowledge hikers are using these tools already and see a way to complement them somehow, I think you want to let the user directly reference their tracks/routes from within Ambulate as it's unlikely they'd like to replicate their work in another tool.
There are certainly a lot of powerful route building tools out there.
Ambulate supports importing tracks/routes GPX files, such that route planning could be done in e.g. Gaia or CalTopo and then exported as GPX and finally imported to Ambulate.
On a similar note all routes in Ambulate can be exported as GPX, so they can be imported to other tools e.g. navigation apps or GPS devices.
AFAIK neither Gaia or CalTopo have public APIs, but they both seem to support sharing in some form, perhaps it is possible for other applications, like Ambulate, to access routes directly saving the the GPX export/import steps? I'll add this as a issue for further investigation, thanks!
But to the more important stuff: the main tools I've been using for trail/route planning (for over 6K miles) are Gaia and CalTopo. These tools have a lot of route building tools and overlays for both planning and navigation and I guess you don't want to replace these tools and if you acknowledge hikers are using these tools already and see a way to complement them somehow, I think you want to let the user directly reference their tracks/routes from within Ambulate as it's unlikely they'd like to replicate their work in another tool.