As for the low voltage stuff, what you can also do is just stub down into your crawlspace, or for the even cheaper but still appreciated later effect, cut in some holes and use the low voltage cut out boxes, tie a string to them and let them dangle below with a washer tied to them. Then later it will be a lot quicker when you get to those points to run in a quick line and pop in some keystones.
You could also go full on bat-shit low volt crazy which I think any refugees from the Networking forum will suggest (myself included) but you probably don't need to.
Yeah, he won't want to go there
I'd be happy to look at any plans you already have and mark up some suggestions.
As others have suggested, put in low voltage conduit stubs to the crawl. Notposting already went with the pull string suggestion.
I would really not make a shotgun suggestion without seeing a floorplan and layout.
One of my favorite tricks in a two story situation involves low voltage flexible conduit (smurf) and open back boxes. I'll go to the crawl and feed up a tube to the first level and secure. Then I'll go with a couple of runs from there to the upper level. I can use the first hole to pull whatever I want to there and those other locations.
If I have to work an attic, bend the smurf in away from the low clearance at the eaves, and bring toward a central location. Make bends gentle.
If you need to add wire to a tube, be prepared to pull out what is there and pull in the new bundle as a unit.
It is tempting to leave a pull string in and just drag in the new wire, but you can 'burn' a hole in one of the other cables in there and not know it until things get flaky.
These can be that intermittent network problem that drives you crazy.