I've made very basic menus for the towns/castles, ect...
I've posted the images below:
So everything is pretty simple, I will carry on the inventory code into the shops which means I don't have to program much of anything. Buying and Selling items is very easy. To buy I would just add an item you selected to your inventory if you have the right amount of gold. Selling is nothing more then "dropping" an item and receiving gold, so I don't need to a program anything other than adding value amount to the players gold count.
The quest screen shows your active story quest and reward for completing that quest. There will be no side quests, just story quests.
This hopefully will all be done today. Then I will post the final update, and a new entry for Task 9 will be posted.
I'm really liking your UI so far; it is very simple and uniform.