This is how i woudl do it:
fit a POE wifi bridge to the outside of your man cave (like this: https://www.ui.com/airmax/nanostation-ac/) and conectit to a POE switch with a wifi Access point on the inside.
link the bridge to you home access point and you will have internet in your man cave.
try...
Yes, and a long I have installed some,
but with more and more being used over CAT6 and the higher frequencys being used over the cable the interferance gets worse.
there is a lot of detal on this in the EIA/TIA and ISO/IEC standards, not to mention risk of over heating if inclosed and used for POE.
It might be a bit late to post here but, do not run you ethernet cable alongside electical cable.
I wont bore you with the details but in short the electical cable will cause interferance on the ethernet cable.