(I just write this down, because it's on my mind)
I think it's time somebody makes the city hub fm 😉
Technically I see 2 possible ways.
One is where everything takes place inside one mission and you teleport to different enclosed areas of the map to do subquests.
Another is a campaign, but when you do a subquest, the mission ends, but the next mission you load the specific quest-map. This questmap you load is depended on what subquest you start inside the map. Afterwards you load the 3th mission in the campaign which will be the cityhub map again, but via persistant info, changes some things inside the map (for example, you can't do the same subquest twice) and you have more gold maybe, etc, etc. So if the cityhub has 5 subquest missions that can be played in any order, the total amount of missions in the campaign would be 10, but the amount of map files 6. Because if you start in the cityhub map, after each subquest mission, you return to the cityhub map again, except for the last mission. When you make missions later you can add them to the cityhub again and make it bigger.
(This seems all possible with changes made in tdm 2.13 , but I'm not 100% sure. It's at least an interesting project to work on)
I started using Unexpected Keyboard for Android phone.
It's pretty cool, because it has an actual Ctrl key, which you can use to do cut, copy and paste actions via x, c and v. pretty handy in the forums, to move quoted text around for example.
The best thing about not mapping more than like every other year is the awesome feeling to see how far TDM has gotten in all appartments. I can just create some parallaxing cobblestones and walk to and fro and just let the jaw drop