I too recently returned to the game after, oooh, probably a decade. I still had my copy (I don’t throw much out). I’ve put on one or two minor mods I think, but that’s all. Found an excellent post in this subreddit that helped me put in a few changes but if you read the comments on that there’s a link to this site which gave some interesting and useful instructions.
I’m thoroughly enjoying playing this again - I’d sort of forgotten how really good it was/is :)
You don't need to mess with the INI files. Install the Freelancer Unofficial Patch 1.4 and you'll get access to every resolution your computer is capable of, plus the interface will scale correctly. This is what I did on my system, and I also have a 2560x1080 monitor.
You can also get better looking graphics by forcing anti-aliasing and anisotropic filtering in your graphics card's settings.
Edit: Went back looking for instructions and found this: https://www.reddit.com/r/freelancer/comments/2g93u6/2014_freelancer_graphics_mod_only_guide/
So, you do need to install this patch...but then you also need to install Jason's Freelancer Patch 1.2. THAT patch is the one that fixes the resolution issues. My bad.
If I remember correctly, I used Lutris with this recipe to install Freelancer on Arch Linux, then installed the Discovery mod manually (using wine on the console). Reading this thread may help. I also needed to add a few more DLLs that converted from DX8 to DX9 to Vulcan to get proper graphics and performance. So it's possible to get it to run fully but it's somewhat hard compared to other Windows games. Unfortunately I can't recall a step by step guide but if you have any specific questions feel free to ask and I can look stuff up.
How did you convert the file? Have you tried any other software for mounting? IIRC, you can get a piece of software called MagicISO or MagicRom or something. On mobile, will check.
EDIT; MagicDisk http://www.magiciso.com/tutorials/miso-magicdisc-history.htm
Dunno if I paste link, but here goes: https://pcgamingwiki.com/wiki/Freelancer
A lot of different fixes there. I think the Widescreen section might help with the font issue, either through Jason's patch or manual ini editing. I got it to work somehow, just don't remember the exact steps.
https://pcgamingwiki.com/wiki/Freelancer#Widescreen_resolution
This is the method I used, and it worked perfectly! There are some minor graphical glitches on a few planets, but the game looks great regardless.
Kind of a weird place I guess, but a quick google search turned up [this PDF on moddb](https://www.moddb.com/games/freelancer/downloads/drizzt40s-ship-creating-tutorial-15). I gave it a quick once over and it's pretty good.
I don't know why they did choose that confusing version number. The patch is definitely newer than the 1.4 one and the changes 1.4 made, are even included in it. 1.4 was named unofficial though since it was a community patch, so it might be that the 1.2 should add a more official flair to that patch.
Did you right-click on the .exe, go to Properties/Compatibility and select Run as Administrator and Compatibility to Windows XP SP 3? Like it is recommended for installing anything FL related? A further problem might be that, beginning with Win 7, the games folder is especially protected and therefore it's often easier to install the game to another folder like c:\Freelancer or whatever. Problems with the folder protection can alternatively be solved with Total Commander from www.ghisler.com, a file commander that offers to switch to Admin mode.
/u/Krossfireo is spot on.
A quick search on Amazon came up with a ton of places to get it cheaply. Click here
For mods and anything Freelancer related that isn't a copy of the game itself The Starport is the place to go.
You're best bet is to start here
Honestly, if you're on Win 7/8 (and 10 I assume but I don't have it) you should be pretty much good to go installing Freelancer out of the box. You can get cheap legit copies on Amazon.
I have't dipped TOO much into the graphics mods but Starport is the place to start!
Good luck!