Before we jump into the leveling system I came up with and how it can be integrated into Fallout 2, you'll want to get the Fallout 2 RPU mod and a couple others. I'll list them here. Follow the directions, tips, etc carefully. BTW, if any links don't work, notify me immediately.

Fallout 2 RPU: https://github.com/BGforgeNet/Fallout2_Restoration_Project#installation
Fallout 2 Tweaks: https://github.com/BGforgeNet/FO2tweaks
Note: Fallout 2 Tweaks contain some really handy config files such as the ability to have virtually unlimited carry weight without installing the Expert Pack Rat mod and the option to reach Level 5 upon completing the Temple of Trials.
ACE-Supercomputer enhanced: https://www.nexusmods.com/fallout2/mods/38

Note: For some reason, whenever I've used the Talking Heads Addon mod along with Talking Heads Actually Talk (THAT) mod, the game randomly freezes/CTDs. If anyone has experienced this issue but found a solution, pls let me know.

I'm including the system I came up with here:

100,300,600,1000,1500,2100,2800,3600,4500,5500,6600,7800,9100,10500,12000,13600,15300,17100,19000,21000,23100,25300,27600,30000,32500,35100,37800,40600,43500,46500,49600,52800,56100,59500,63000,66600,70300,74100,78000,82000,86100,90300,94600,99000,103500,108100,112800,117600,122500,127500,132600,137800,143100,148500,154000,159600,165300,171100,177000,183000,189100,195300,201600,208000,214500,221100,227800,234600,241500,248500,255600,262800,270100,277500,285000,292600,300300,308100,316000,324000,332100,340300,348600,357000,365500,374100,382800,391600,400500,409500,418600,427800,437100,446500,456000,465600,475300,485100,495000,505000,515100,525300,535600,546000,556500,567100,577800,588600,599500,610500,621600,632800,644100,655500,667000,678600,690300,702100,714000,726000,738100,750300,762600,775000,787500,800100,812800,825600,838500,851500,864600,877800,891100,904500,918000,931600,945300,959100,973000,987000,1001100,1015300,1029600

Level 12: 6600
Level 24: 27600
Level 36: 63000
Level 48: 112800
Level 60: 177000
Level 72: 255600
Level 84: 348600
Level 96: 456000
Level 108: 577800
Level 120: 714000
Level 132: 864600
Level 144: 1029600


Addendum: The game engine is capped to level 99 and you can't go beyond that as far as I know.
The Level 99 Cap Key is this: 485100
If I find some talented modder out there who can find a way to break this barrier, I'll let you all know and make a new guide.

You need to go to the ddraw config file in the Fallout 2 main folder, open it with Notepad, CTRL+F, find: Player's level is capped, and you should come to this line of code:
;Uncomment and set a comma delimited list of numbers to use a custom xp table.
;Player's level is capped once the highest specified level is reached
XPTable=(Insert XP numbers)

IMPORTANT!!! You need to remove the semicolon in front of XPTable= or the changes you make won't register in-game.

Basicallly, you want the code to go from this:
;Uncomment and set a comma delimited list of numbers to use a custom xp table.
;Player's level is capped once the highest specified level is reached
;XPTable=(Insert XP numbers)

To this:
;Uncomment and set a comma delimited list of numbers to use a custom xp table.
;Player's level is capped once the highest specified level is reached
XPTable=(Insert XP numbers)


Once you've made your changes, start a new game and play through the ToT as usual. You'll level up a fair amount in there but it's when you complete the temple where things can get really interesting depending on whether or not you've configured the FO2 Tweaks to boost you to Level 5 upon completing the ToT. Follow me to the next Section where I show you how that looks like!

Go into FO2 Tweaks and find the line of code that reads:
; level 5 after completing temple of trials
level5=0

Change that 0 to a 1 so it reads:
; level 5 after completing temple of trials
level5=1

Once you've made your character, go into the temple to begin the trials. The following screenshots will relate to your character's stats upon clearing out each floor and reaching the door to the next room.

Room 1:
-
Room 2: (I went out of my way to disable as many floor traps as possible)
-
Upon Leaving the Temple:
Look at all these Perks!
-
FOUR PERKS UPON COMPLETING THE TEMPLE OF TRIALS!!!!

How about those Skill Points? Well...
The Skill Points may read 99 but if we sink 62 of those points into Traps:
We now have 98. In reality, we earned 160 Skill Points upon completing the Temple of Trials with that one line of code we altered in the Fallout 2 Tweaks mod.
Super cool right?
So! You know how to make yourself the strongest Wastelander around! Go! Become Ruler of the Wasteland! Fight! WIN!!!!
And call me on my Discord, you know how much I enjoy discussing these old games. C;