Wiremold is a puppy mother to work with but beats opening walls unless one is real good at snaking Romex.
As for a lack of circuits in upper floors there are a number of Code compliant ways to deal with that.
When I purchased my first home it was a 3 story 6/2 structure in SE Lauderdale that was built in the 40’s, the living spaces had been electrically upgraded in the 70’s so they where all three conductor circuits, however it had an attic that one could stand up in and had hardwood flooring, someone was remodeling it to be used as a large 12′ X 22′ room.
I wanted to use it as a studio but two problems no power and very little ventilation.
To solve the problem we installed a 100 amp sub panel next to the service entrance from there ran a ¾″ EMT conduit up the real wall of the home into the attic where we installed a 100 amp load center.
That allowed us to install 4 outlet circuits and 2 circuits for through wall A/C units, once that work was complete the walls and roof where insulated and drywall was put up.
With that work out of the way I dampened the studio and control room with 2′ X 4′ X 1.5″ panels containing fiberglass FRK sound deadening insulation boards, that room was dead, no reflections what so ever and very neighbor friendly, those panels worked so well I am to this day still building them for folks who need them for home VO or musical recording facilities.
That attic worked well, better than we expected and being in a home I could rent out the space for a considerably lower rate then what they would pay to book a room down at Criteria and better than that I had a number of spare bedrooms for folks to crash out in.
We had a lot of fun up there and made a s-load of 4 track demo tapes over the years, some of which got a few local bands their start.
So yea attics can be repurposed if done properly with a little forethought and planning.