I'm probably a majority of the way through this just cause I've been putting Trek on as background noise while I work on repetitive tasks.
Starting probably in the fall, I've already seen all of DS9 and all of Voyager except for Threshold, Fair Haven and Spirit Folk. I'm in season 3 of TNG, and I watched a full season of Enterprise. If I wanted to pull off this challenge I could probably do it without even forcing myself to.
Just make sure you have a natural time in your day where you want to watch Star Trek, so you're never forcing yourself to.
Maybe a little advice if you're serious about trying this. Don't necessarily try to watch them in order. Maybe, start two or three of them, and jump between them so you have variety, and just watch the individual series internally in the correct order.