I confess I've not played the Paradox titles, but I played the heck out of GTA 1 and 2 back in the day. I actually really hated the main missions and so forth, but I adored just using the game as a big sandbox. I'd use cheats to let me access the later cities and then just play around in them, too. So I totally get where you are coming from!
The interesting thing about TLF is that, largely like GTA, there's nothing to particularly stop you from doing this right from the start. I mean, the solar system will eventually crumble around you, but you'll have quite a long while to play prior to that happening.
That said, if it turns out that there are some things that would be good options for letting us make that sort of sandbox play more fun or interesting, then certainly those are things we can look at for Advanced Start options.