Crabgrass took over our yard this year. I heard on a gardening show recently that you can rent a device, sort of like a lawnmower, that will thatch your yard as you drive it around, and then also put down grass seed at the same time. This sounds great, but what do we do to get rid of the crabgrass first? I have always been vehemently opposed to poisons or spraying the yard, but it seems unavoidable. Are the honeybees not out now? I live in zone 6. Thank you so much for any advice!

Crabgrass is an annual and about now will be dying out. While it is getting almost too late this fall you may still have time to overseed that yard which next spring when the soil warms enough for the Crabgrss to germinate and grow your turf might be thick enough to prevent that.

Yes, get a good crop of strong turf and in a couple years (or 3 or 4) it will be high enough to shade out weed seeds to a large extent.
Your acreage sounds though like you should plan to put down next June/July a covering of pre-emergent. This does not kill crabgrass, it prevents most of the seeds it puts out to develop. So the next year you should have less.

Pre-emergent cannot be used during re-seeding periods--one would counteract the other.

A timely schedule of fertilizing/watering/seeding will improve the quality of any turf grass.