You'll need to agree any cables routes with the VM tech. Options will depend on your existing cable routes and what you consider acceptable from an aesthetic POV. VM techs won't lift floorboards. Cables are surface mounted.
Much will depend on the individual technician who turns up and their level of skill, knowledge and interest in doing the job. We hear wide-ranging descriptions of these visits on here. Some customers describe a visit from a well-motivated technician who is keen to do the job and does so with minimal fuss. Others describe a polar-opposite experience.
From your description the simplest approach sounds like fitting a phone socket upstairs next to the hub, then running a phone cable following the same path as the existing coaxial cable which supplies the VM hub. The new phone cable would go outside and join to the other phone cables in the plastic omnibox outside or into one of the existing phone sockets.
VM uses an adapter lead from the hub to the adjacent phone socket to 'backfeed' a connection from the hub into the existing phone wiring. Past example below
https://community.virginmedia.com/t5/Forum-Archive/HUB3-to-Master-socket-adaptor/m-p/4507007#M262932...
The no-wires solution is to invest in some cordless phones. Plug the base station into the VM hub and use the satellite handsets around the home where needed.
