I use ABS to host my audiobooks and I use the Android app to download them to a folder, and then use Smart Audiobook Player to play them. It works great, though you lose the time syncing with the server, if you care about that.
Same here. I do this because ABS android app would not accurately track my listening progress, and is very frequently off after a pause. May be off by 30 min, by an hour, gets rather frustrating relistening the same segments. Was never able to solve this.
There are also alternative clients, like Lissen.