Yes to both. For the overworld, I haven't decided yet on random or static, or a mix of the two. Either way it is going to be large, with towns and special locations. The dungeon locations will be randomized on the map and each main dungeon will be devoted to a single item (crown or jewel) with a boss fight at the end for the particular item. There will also be side dungeons for loot gathering, XP farming and such. I want to implement side quests for special items too, so there will be a lot to explore and find.
There is quite a bit that will be going into the overworld portion of the game. There will be a full economy, with taverns and inns that the player can use as a base of operations, a banking system, various types of shops, and guilds which will house training centers and specialized shops.
The banks are going to be a key portion of the game. Each bank has vaults that can be rented and can be used to store valuable items. The vaults were made by the Wizard Guild at the request of the Banking Guild and are persistent across the overworld. It doesn't matter which bank you go to, you can always access your vault and items.
The dungeons will be persistent, so once you clear a dungeon it will be cleared, except for the occasional random spawn that may happen if you re-enter the dungeon. Once thing I am going to implement is the monster spawner that I first saw in the old game Gauntlet
(they are also in Minecraft but this was not the first implementation) that will offer some extra challenges.
I am going to build a room editor for the dungeons which will be used to create pre-defined rooms. There is a random chance that a predefined room will be used, and may contain a chest, altar, fountain or spawner, or maybe just a fancy-looking room. Altars and fountains are bonus locations where you can enchant items or gain a random buff or, if you are unlucky, a cursed item or debuff.
One thing I am going to do is limit items to drops and chests. There will not be items laying around on the floor like in most RL games. This is going to add an extra challenge while in the dungeons since items are going to have limited availability. However, you will be able to pick up chests, so you can use them to store items for later retrieval if needed.
Items are also going to be limited use over time. Armor will be ablative, like in Doom, and will wear down with use. The same for swords and such. You'll be able to repair items though, add enchants to items for increased durability, and craft new items. The point here is to keep the player managing resources and to keep them from becoming overpowered over the long term. Resource management will be a key element in the game.
Well, this was a long-winded answer, but yes, the world will be persistent and have a lot of interaction in it. You'll be able to tunnel through and into dungeons, collect resources that you find (gold and mithril for example), build and craft, use spawners as XP farms--a whole host of things not normally found in an RL game. You could really categorize this game as a sandbox RL-RPG with a solid set of goals and clear end-game. It is open-ended though, so you can keep playing after you win the game if you want as there will be a lot you will be able to do and accomplish.
Obviously, this is going to take a while, but I am going to release early and often, so you'll have some play time with the game as I move along. Right now I am slogging through the data portion of the game, but once I get through that, the updates should be out on a regular basis.