Pulling wires through the ceiling means you have to fish the wires through the tightly framed trusses, and then there's the insulation to get snagged into, not to mention other wire bundles. As stated, the wire molding option is a clean, easy, and fast solution.
A couple of years ago I had my roof completely off down to the trusses (major moisture issue..., resolved) and got a good look at the construction, IMO not very conducive for fishing wire through "after the fact".
ps: Did the stat mod as well (Hunter) , nice to have a plus/minus 1 degree heat and A/C inside environment control!
2016 GM 2500HD 6.0L/4.10
2005 Jayco Eagle 278FBS
Reese HP Dual Cam
Putnam Class V