WHAT IF GOKU AND GOHAN HAD ENTERED SPIRIT ROOM BEFORE VEGETA AND TRUNKS - John D.

Cell kills Tien,since Goku is not there to teleport and save him.Goku and Gohan get out of rosat and go to fight Cell.Vegeta and Future Trunks enter the room.Goku and Gohan beat Cell.
Then,they discover the injured Piccolo and take him to the Sky Palace,where he is healed.Vegeta and Future Trunks get out from the room.Tien is revived by dragonballs.Future Trunks
returns to his timeline.
7 years later:

-Goku,Vegeta and Gohan are all weaker,since they haven't transformed into SSJ2.
-Piccolo is weaker,since he hasn't trained in rosat.
-Trunks and Goten have the same strength.

At Babidi's spaceship:

-Vegeta beats Puipui
-Goku has trouble against Yakon and transforms into SSJ.Yakon sucks his aura.Goku can't go SSJ2 to make Yakon explode,but has another idea.He asks Vegeta and Gohan to
transform into SSJ too.Yakon tries to suck all three auras and explodes.
-Gohan loses to Dabura,but Dabura doesn't kill him because he discovers Vegeta's evil.

Majin boost turns Vegeta into SSJ2.Goku and Vegeta are teleported by Babidi to the desert and start fighting.Gohan and Shin try to stop Buu's shell from hatching.Meanwhile,Vegeta dominates the fight with Goku.Goku takes an enormous amount of damage,causing Buu's egg to hatch.While fighting Buu,Gohan transforms into SSJ2 for the first time,but still loses.Dabura is killed.Vegeta arrives and commits suicide in order to kill Buu,but his sacrifice is futile.

Goku,Piccolo,Trunks and Goten all enter spirit room to train(Goku does not know fusion dance).Goku stays for 1 day(since he has already spent
1 day there).The other three stay for two days.Piccolo becomes about equal to Perfect Cell.Goku,Goten and Trunks all go SSJ2.At this point,
Super Buu approaches the palace.The four Z fighters lead him back to Earth to fight.Super Buu easily beats all 4 of them.When he's ready to kill
them,Gohan arrives,having trained with Z sword.He also loses.

When everything seems lost,Hercules appears.Super Buu undergoes an inner collision,which splits him into Kid Buu and Fat Buu.The two Buus
start fighting.Meanwhile,Dende arrives and heals the gang.Fat Buu can't fight any longer.Under this pressure,Goku transforms into SSJ3 for the
first time.He starts fighting Buu and they are even,until Goku starts getting fatigued.Then all Z fighters give him their energy,but it's not enough
to finish Buu off.But,at that moment,Vegeta appears(having returned with special permission).Vegeta also gives his energy and Goku attacks with
Dragon Fist killing Kid Buu.Vegeta is revived by dragonballs.