This page outlines some tips for wiring your location for DSL.
In most homes there is a box or junction just inside where the Bell line enters your location. This is called the demarcation point. All the wiring inside the demarcation point, along with any associated problems, are owned by the building owner. All wiring from the demarcation point going to the outside world are owned by Bell and are their responsibility to repair. Usually there is one line going into the demarcation point from Bell’s outside lines and then one wire coming out of the demarcation point which connects to all the phone jacks in your house.
Instead of putting a DSL line filter on each device attached to your phone line at your location (except your DSL modem, of course), you could put one line filter at your demarcation point for your whole house. That would involve installing a jack at the demarcation point, then a splitter to create two parallel jacks. On one jack install a line filter and connect the house wiring to that line filter. Then connect the line to the DSL modem to the other jack.
This is optimal for many reasons:
But there are shortcomings to this method too:
There are junction boxes made for this, with built-in DSL line filters. These may also possibly have higher quality filters too.
Ethernet cables can be routed through heating ducts. One way to feed a cable through a long, curving duct is to tie a paper tissue to a thread and then blow the tissue through the duct using the exhaust from a vacuum cleaner. The thread can then be used to pull a string through, which then can be used to pull an ethernet cable through.
Of course wireless is one way to avoid all the hassles of cabling, but it provides a slower connection than ethernet, may suffer from interference and must be operated in a secure mode to avoid privacy and security issues.