Chemist's knives / herbs and most rope are not useful (except as atmosphere). The only 4 rope in the game that you need are close to where you will need them, in the easter egg area.

Silver Armour and Treasure Maps


I always saved before attempting to steal, so never got thrown in jail. Depending on the jail you may be able to find a lockpick in the cell. A technique for getting Commander Ralph out of his back room (if you had entered previously and gotten kicked out) involves leaving a teleporter stone in the cell before trying to enter his room and letting yourself get arrested.