Fun thread, I love such challenges. You didn't ask, but here is an alternative route that will be much safer and much slower.
Killing Hell Andariel all the way to level 99.
At level 98, Andariel yields 64 XP (out of her original 215794 XP). You would need to kill her 4547790 times to get the 291058498 XP required to go from 98 to 99.
If you can kill her twice per minute with tele sorc for 8 hours a day (like a normal job), then you can go from level 98 to 99 in a little under 13 years easily.
At level 97, Andariel yields a whopping 85 XP, which turns into 9 years of grinding from 97 to 98. I.e. you need 22 years to get from 97 to 99 this way.
If you a worried about teleporting into dangerous Hell monsters (should be no issue in the high 90s) though, then you can also go ultra safe and just farm Nightmare Andariel.
Unfortunately she only gives 16 XP at level 98, so you will need 52 years for the final level then.
Hope this was helpful.
All the best
Graskian/Klodrian/Jintian/Fiskeørn
Might be the best post I’ve seen in 13 years on this forum