I really don't see the point of the requirement for a solo CPL QXC.
You have to fly a cross-country to get a PPL. That's fine, you need to demonstrate that you can navigate your aircraft away from the local zone unaided.
However, doing the same thing again but a little bit further this time requires no extra skills whatsoever. So what's the point?
Furthermore you could cock up the flight, get hopelessly lost, bust airspace and require radar vectors from D&D all the way around your route but provided your logbook shows the flight was over the required distance that would be deemed OK.
A pointless requirement in my view. But good luck to the OP anyway