Welcome to Project-GC Q&A. Ask questions and get answers from other Project-GC users.
If you get a good answer, click the checkbox on the left to select it as the best answer.
Upvote answers or questions that have helped you.
If you don't get clear answers, edit your question to make it clearer.
I added a feature request regarding one part of your question: "Several modes of input should be provided"
gpx-import would be nice to satisfy the need of adding heaps of caches.