Warning:I think landless characters are hardcoded unplayable, atleast for me, similar to theocracies. You can play landless but when I try to load a save as landless it says not allowed to play. That aside should be functional. Note from Skoran: So I found a way around not being able to load into your landless adventurer directly: If you click continue instead of load on your saves, it puts you directly into your character instead of having to use the console.
This will allow you to jump out of your titles into a landless band, entrusting the titles to your Chancellor. Complete with 1000 troops and raise of fleet of 20 galleys to ferry them.
You can also become landless by losing your last demesne while not a prisoner.
While landless you can raise a force of adventurers to wander the lands. And even forge a claim on an independent title. As well as a join defenders diplomacy so you can merc yourself out.
To get you an income, while in command of a force, the neutral(opinion >0) province owner of your location will gift you some gold. Limited to once per year per province owner.
Also there is a money flavor event each for lawful and lawless adventurers.
Once you grow weary of wandering you can resume position.
Added New Mechanics; Invite to Band, Landless Marriage, and Move Band.
Invite to Band allows pulling courtiers from other realms to your band.
Landless Marriage sets a union between a Landless Ruler and one of their court
Move Band moves your band's location to a new province you don't have a claim on. Available through a title diplomacy(right clicking on the county's flag)
Setup Shop if your band is in a silk road province, you can open a shop. So long as you aren't in command you'll receive monthly profits, profits will increase over time as your shop grows. If you move your capital, it will disband your shop.