The "sav-to-map" trick works for both Stronghold 1 and Stronghold Crusader. It is very useful for mapmakers who want their maps to, like in the campaign missions, start with workers already assigned to their workplaces.
The first step is to either make a map of your own, or pick an already-completed map to experiment with. If the latter is a map that another person created, please do not take credit for it! In fact, this option should only be used in order to familiarize oneself with the sav-to-map process!
If you made your own map, make sure the terrain, buildings, and troops are where you want them, so that way you only have to convert the map once. However, make sure you have some houses and workplaces put down before you save. For purposes of this tutorial, we will use a well.
Do not add any invasions or events. Do not bother changing the date either. You will see why later, but wait to customize these until after the conversion.
Now, open the map in the appropriate screen ("Custom Map" for SHC, "Invasion" or "Economic" for SH1). Wait until your peasants around the campfire go to their workplaces, including that well-worker. Remember, all the goods (resources, food, weapons) that are produced now will be added to the scenario's starting goods, unless you delete and replace the stockpile, granary, and armoury with the final touches.
Save the game when you are happy. If you do not edit the map itself later on, but only the scenario settings, this is where your workers will be. If you plan on changing the map, save a little in advance. Note that no peasants will become employed in the map editor, but employed peasants will continue to work.
For this tutorial, we will call the save file "Test" so we can easily locate it.
Before we can perform the actual trick, we need to locate the files on your computer! For a player's own saves and maps, and the suggested location for downloaded files, for Windows 7 is:
Here, there are two folders we should concern ourselves with: Maps, and Saves. Open the Saves folder and find our "Test" save. Now, right click on it, and COPY it to your desktop. Keep the original Save file in case of an accident.
The next step requires some tech expertise. You will need to change the file extension name from "test.sav" to "test.map" - for this, right click the file and rename it.
An easy way to see file extensions is to do the following (for Windows 7): click the start button, type "show or hide file extensions" into the search bar (or find it under the Control Panel), under the advanced settings "View" tab make sure that "Hide extensions for known file types" is NOT checked. Click "Apply" and close the window.
This can also help with situations so you know you won't have a weird (and probably corrupted) "test.map.sav" file.
Let's hope you kept that Documents folder open. Drag your new "test.map" file into the Maps folder. Restart your game. Now if you play the map, you will notice the well-worker is sitting by his well or where you left him, same with the rest of the workers. Note that a well-worker is not necessary, but I figured it would be a nice example.
Now you can edit your new map as usual. You will notice that your workers will be continuing their jobs but no new workers will be hired, so make sure enemies and lions are far away, otherwise your efforts will have been wasted! While it is not reccomended that you further edit the map itself, you may wish to replace the stockpile and other places where resources have been gathered if you wish for an exact amount of starting goods for the player.
If you wish to halt those pesky peasants from bringing in more goods as soon as you replaced the buildings, you can either press Alt+H to pause movement in the editor, or decrease the game speed in the options menu as usual.
For the final touches, create the scenario settings by adding starting goods, objectives, invasions, and your usual Custom Map features. Save when you're done.
Congratulations! You have just completed your first "sav-to-map" mission! While the process may seem lengthy at a glance, the results pay off and after you do this more than once you will be able to (almost) perform this operation in your sleep! Now you can go and make that massive city that you've always wanted to defend, without having to see all of those ugly, red "this building has no labor" markers!
Alternatively, if you are in freebuild and don't want your utopian castle to go to waste, why not turn it into an invasion map where you have to defend the very same citadel that you've spent hours making? The possibilities are endless. Enjoy!