computer --acrossHouse-- hi-fi? (Boss says "SEE NO WIRES!")

(Why the effort: hi-fi has vintage-1969 BOSE 901 incredible-sounding
speakers, backed against old-house HARD plaster wall
(ideal/required for the 901's audio backwards-reflection scheme).

Method 1: Buy cheap computer for hi-fi AND HOPE wifi reaches (6 plaster
wall-faces; see below).

(Yes, wifi, transmitted from kitchen computer-site, does nicely
reach laptop in basement, but that path is through only ONE wall
and one wooden floor.)

Method 2: Hang cable from ceilings: kitchen (where PC is), across
front hall, living room, and into where hi-fi is. (GUARANTEED
RESULT: end up living on the street or in the car!)

Method 3: Hire electrician to run cable out kitchen window, around
back of house, & into hi-fi's window.

Method 4: MY DESIRED IDEAL: (wireless scheme) Concoct scheme to
transmit wireless signal from computer, received at hi-fi amp.

Distance: 13 yards;

Impediments to wireless transmission: must go through three OLD
1945 HOUSE walls, each surfaced with heavy plaster, probably backed
with wire mesh, thus 3 * 2 = 6 layers of it (ie one layer on each
wall face).

Question: how to implement such a solution -- and at a reasonable cost?

THANK YOU!

David