I have run many HAM RADIO RG cables thru the air conditioner ducts for one end of the trailer to the other in my 5th Wheel. I just pull down the duct vents and fish a cable from duct to duck until I get to where i need to go. They are only 6-feet or so apart.
You may have to penetrate the ceiling area when you get to where you want your cable to come out hopefully in the inside of ceiling cabinet etc. I was able to get my cables from point A to point B in good order using the A/C Ducts.
If I penetrated the ceiling areas I would fill them with spray in expanding Insulation foam. Never created any problems with the normal flow of air conditioning...
Might work for you...
Roy Ken
My Posts are IMHO based on my experiences - Words in CAPS does not mean I am shouting
Roy - Carolyn
RETIRED DOAF/DON/DOD/CONTR RADIO TECH (42yrs)
K9PHT (Since 1957) 146.52M
2010 F150, 5.4,3:73 Gears,SCab
2008 Starcraft 14RT EU2000i GEN
2005 Flagstaff 8528RESS