Obligatory link: https://blog.garrytan.com/travel-planning-software-the-most-...
Features - Manage itineraries - Add activities and map markers - Add routes (upload GPX or plot by hand on map) - Desktop and mobile
It is free to try (login using Google or create a user). Alternatively the slides on the home page give an idea of the UI.
I'll appreciate any thoughts and feedback you care to share:)