To use something like a cookspit, alchemy table, ect would you just place a patrol idle marker near it? Link to the object itself instead? I'm trying to get a servant go to a cookspit then go to a table and use the servestew idle marker three times per day but only do each action once each time not pingpong back and forth.
NPC's automatically use those furniture markers as long as their package is some form of 'sandbox' and it has Furniture checked. Maybe you could make a travel package going to the servestew idle and give it a 30-60 minute window (Schedule), then check 'Ignored by Sandbox' so the servant only uses it when directly told to via the package.
Give it a value under patrol data in the reference window, and go from there. That will make them stay at the table, cookspit, etc for a defined amount of time (if they are in a patrol package).
I just used a Patrol Package and picked the cookspit as one leg of it by clicking on it as a reference in the cell. Set the time to cook in the patrol data tab.
If the patrol package didn't fit your plans in any way, keep in mind that all the crafting furnitures are seats to all effects. You could just use a sit package with the cookspit as objective.