Homestead locations are unlocked by finding Star Stone. If you find star stone, it automatically unlocks whatever is next in line at your homestead.
Blood stones are Star stones that have been filled with blood. Using them reverts them back to star stones, which you then immediately absorb for more things at your homestead.
Aside from these vendors, other vendors should be upgrading their stock as well (they upgrade/change their inventory every time you level up and come back to trade with them). If all else fails, you can get to 5 crafting and create your own skill books.
