There was a project called "GTA V To SA" by xxGTAXIVxx & THBP they long time they didn't uploaded more missions 
You will find old missions and random events here

"http://gtaforums.com/topic/670946-gta-v-to-sa-xxgtaxivxx-thbp/"

So I decided to make Last mission of the series the third way by iFaizan

NOTE: This mission is really big so I divided it into 6 parts first 2 parts having intro and mission's starting cutscene and the others have gun fights

Story

Agents Steve Haines and Dave Norton task Franklin to kill
Trevor Philips, due to him being a liability, despite having
saved both of them. Later, Devin Weston shows up at 
Franklin's house and tells Franklin to kill Michael De Santa, 
due to him also being a liability, for Molly's death and his
failure to kill Michael's family. Weston then gives Franklin 
three options. A, listen to the FIB Agents, or B, Weston
himself, or C, try to save both of his mentors. After Weston
leaves, Choosing C leads to this mission, and has him call Lester.

Protagonists

Franklin Clinton
Michael De Santa
Trevor Philips

Antagonists

Devin Weston
Steve Haines
Stretch
Wei Cheng

Friends

Lamar Devis
Lester Crest

Crowed Enemies

NOOSE
Merryweather Security
FIB
Ballas
Wei Cheng's Mafia

Conditions of mission failure

Protagonists Dead(Wasted)

If Franklin dead
If Micheal dead
If Trevor dead

Protagonists Arrested(Busted)

If Franklin arrested
If Micheal arrested
If Trevor arrested

Protagonists Car Dystroyed

If Franklin's vehicle get dystroyed
If Micheal's vehicle get dystroyed
If Trevor's vehicle get dystroyed

Friends dead

If Lamar dead
If Lester dead

Video walkthrough of GTA 5

https://www.youtube.com/watch?v=cQ4luP7QVHs!!!

Installation

This mission require DYOM 8.1 if you don't have it download it from here
"http://www.gtagarage.com/mods/show.php?id=5038"
Download latest version then the game will work then extract and put all files in my documents> GTA san andreas userfiles
and then put all this folder's files into gta san andreas user file folder then start new game choose "design your own mission" option
And wait till the game loads then press "Y" to load and choose missions 
Have fun :)

Contact me

http://gtaforums.com/user/801406-ifaizan/ -GTA Forums profile
http://dyom.gtagames.nl/profile/2736 -DYOM profile
https://www.facebook.com/UIF.iFaizan -Facebook profile

Credits

Last mission of the series GTA 5 "Third Way"- iFaizan
Grand theft Auto San Andreas 1.0 en - Rockstar Games
DYOM-Design Your Own Mission - Dutchy3010 and PatrickW
Previous missions of GTA 5 - xxGTAXIVxx & THBP