I really like your idea for the initial game. I was thinking about how it could best be done and I have some ideas...
I think that trade would probably fuel the majority of exploration and activity. The entire world would start off with a hidden resource map under it being procedurally generated based on some geology/geography influences. Everything will require resources in some way.
The game would be mainly focused on empire building from the ground up. The world would start off with a few major cities throughout the world, which would serve as optional starting locations. These cities would be procedurally generated down to the building but with given random features for each(residence/commercial).
Commercial buildings could be bought or built, but depending on function, could be more or less successful. These businesses would have certain attributes which could make them more or less competitive. Most businesses would perform basic functions like converting one or materials to another material. Businesses, depending on capacity, would require a certain number of workers, thus requiring overhead costs and promoting residential development.
Level 1: The Beginning(optional)
The player will initially enter the game at one of these starting cities, with a given amount of money(starting at a car dealership/train depot/airport). Initially, the objective of the game will be to make money. You can do this by solving the various resource needs of the residents of the beginning city. All the trade characteristics of the city will be presented to you in one panel. Choosing a single resource will show all the places in town buying/selling that resource. For steel you might see Steel Factory[Sell: 42/unit] and Vehicle Factory[Buy: 55/unit]. From this you could see that by driving some steel across town, you could make $13/unit profit(- gas cost). Likewise, from the pilot's perspective, there might be mini missions that require you to crop dust or fly mail to a nearby city.
Throughout the game, the trade secrets of each city would become available to you as you explored them. After a certain amount of money has been made, you would be upgraded to Level 2, where additional features would be available.
Level 2: Empire building
Level 2 would allow players to build an empire. An empire is loosely defined as a set of assets(businesses and/or vehicles) and vehicle routes. Routes could include:
-Purchasing material at one end, travel using a vehicle(plane/truck/train), selling material at another
-Can set up vertically integrated businesses with routes simply being the action of relocating material(in this case, will cost you money instead of gain you money)
-Requirement of actually running the route yourself for the maiden voyage(have to fly it yourself first)
-In this case, you might be able to record route as a vector path to recreate as "AI" or just for route run time
-Routes could be run by the player or turned into hired jobs, which would be flown by either AI(vector recorded or otherwise) or by other players(contents could be hidden) for the same cost(or scaled based on quantity).
-A vehicle will be required for the mission for AI completion, but not for player completion
-These routes may be visually displayed to other players if capability exists
-The Routes would be traveled as regularly as possible(in real time) based on conditions provided(vehicle availability/profit conditions)
Prices will usually be a function of supply/demand, and thus as supply approaches requirement/holding capacity, selling prices will decrease. For this reason, routes will be conditional based on profit/unit. Vehicles could even have a route queue which priorities profit/hr. This could essentially turn into a sort of airline tycoon type trader game in this respect.
The other main part of Empire building is about the specific businesses. There will be businesses focused on raw material gathering(think mines,farms, logging companies, fisheries, oil rigs), refining companies(like sawmills, steel factory, oil refinery), manufacturing companies(car plant, airplane plant, construction company) and even storage/distribution centers. Each will have their respective inputs/outputs with the exception of mines/logging companies.
These raw material companies would be placed based on the results of prospecting(literally an action your character should be able to do anywhere). This will give results of the land and you can interpret it how you wish. Obviously, trees are a non-hidden resource. A logging company set in open plains will likely not have good yields.
If a player was to randomly build a logging company out in the middle of nowhere, depending on size(like level 1, 2, 3 etc), it would require say 50 employees. These 50 employees would set up residence near the business in the form of small houses. Because of those employees, maybe a gas station would pop up and a small grocery store. this would increase the resident number by a little more. If you chose to add a sawmill and upgrade the size of the logging company, the population would increase again, prompting more houses and maybe a small school. Over time your congregation would become a town and depending on how much you contributed yourself, you might be able to name it/control it(though going into that might be too in depth). These towns would be procedurally generated off the initial placement of companies.
The Economy
All of this is driven by the economy. Much of the price will be determined by the distance the resource is away, the difficulty(weight/space requirements) to obtain and the trade infrastructure currently in place. Planes will be more expensive because of fuel and weight/space requirements. Trains may be cheap on flat ground, but tracks might be too expensive in mountainous terrain. Track royalties/space requirements may also apply for trains. Vehicles and construction materials will likely be the main consumption of player resources, but things like food and transportation will be required by the cities as well.
Ultimately, your "Empire" could be anything from a transport company, to a vertically integrated plane manufacturing company to a General Empire dabbling in all aspects. I don't know if this is exactly how all the features would go, but it seems to follow your general idea of what you want in a game and it seems like it would be fun. Also, for the most part, I suspect this technology would work fine off of a large database.
Anyhow, sorry for the extremely long, scattered idea. Any thoughts?
