Ok, good to see some interest. I can tell you a bit more on this.
This will likely be in a parallel world to the one in Fate, much like Apocrypha is. All of them are connected via Akasha (The Root) so they are all very similar. Certain things just happened differently. You can assume, if you are familiar with the anime/game/novels that the first two grail wars went off the same way as in those timelines. The difference is that during the third war, the Einzbern family was unsuccessful at summoning Angra Mainyu, and as such the grail was not polluted as it was in the main series. The third war ended with no clear winner, much as the past ones, and while they tried, none of the 3 great families were able to reach Akasha, or in the case of the Einzberns, recover the secrets to the Third Magic (Prophecy/Divination.) Reasons for this are usually blamed on the onset of the second world war, as the 3rd Grail war took place in the years and political/military buildup leading to that.
At the advent of the fourth Grail war, it was discovered that during WW2, the laylines in Fuyuki were interrupted, and the Grail required more time to recover the mana necessary to initiate the War. Further study of the current level of mana revealed that it would be another 15 years before the grail was ready. This of course completely changed the timeline from the core Fate timeline, in that the events leading up to and surrounding Fate/Zero never occurred.
A summary of the state of the 3 families and those associated with original Fate/Zero events:
Kiritsugu Emiya was initially pegged as the master for the Einzberns, but when the war did not start, he opted to settle down and raise Illya with his wife, Irisvielle. Although born of a homunculus, Illya is more human than Homunculi, both in having a soul and a standard lifespan. She is the beginning of the new bloodline for the Einzberns.
The Matou Family adopted Sakura, and at the urging of her uncle, Kariya, stayed their hand in order to allow Kariya to take her place as the potential master in the grail war. However, when the war did not come, Kariya passed soon after, the worms which gave him magic totally consuming his body. Zoken passed soon after as well, spelling a permanent end to the Matou family, save what bloodline lived on in Sakura. Sakura was brought back to the Tohsaka family, and raised with her sister.
The Tohsaka family continued to thrive, and though the issue of two daughters plagued Tokiomi initially, it was decided that Sakura would be apprenticed out to a rising name in the Clock Tower: Waver Velvet. Velvet had made waves among mages after proving his theory that hard work and skill could surpass genetic talent. Tokiomi, ever the opportunist, allied himself with Velvet for his own reasons, as well as the well-being of his daughter.
Both Risei and Kirei Kotomine died, the former of old age, and the latter of suicide, his purpose in life taken once again by the unexpected postponement of the fourth grail war. The respective overseer for the church changed to Caren Hortensia, the only living relative of the Kotomine family.
The fourth Grail war will begin in 2014, 15 years after the failed start.