You can change the font via a map or mod, the difference is that if you do it via a map the changes only apply when the map is loaded. With a mod you are also able to change the Main Menu etc..

Create a new folder called:

 fonts 

In your map or mods folder, here you can place the fonts you want to override. You can find the names in the code below, you have to paste that in your zone file.

ttf,fonts/default.ttf //Menu Text
ttf,fonts/escom.ttf //Menu Text
ttf,fonts/FoundryGridnik-Medium.ttf //Menu Text, No Ingame Changes
ttf,fonts/FoundryGridnik-Bold.ttf //Menu Text (UPPERCASE Letters)
ttf,fonts/RefrigeratorDeluxe-Regular.ttf //Scoreboard & Weapon Name & Hintstring
ttf,fonts/wearetrippinshort.ttf //Score Points HUD & Ammo Counter

Below i have included a example with fonts so you can see the difference.