I think to give outposts greater value other than just a "quick travel" option Takkar can only craft new weapons, arrows and consumables at a "workbench", this would be at either the main camp or at any Outposts you liberate from the Udam.
This would add challenge and value to the travelling mechanics, also I think in the "hardest" setting (or have a more SURVIVAL or EXTREME setting) it should turn quick travel off to really make players strategically decide their movements, time/effort but also preparation.
Maybe take from Red Dead Redemption and set up a temporary camp? The thing with spears and arrows though is that they can be crafted as long as you have the materials. But for other things like a new shirt or pack or something, armor, perhaps only at outposts. I do however agree that the Outposts need more value to them!!!