The umbrella training facility in RE0 was only a few miles a way from the spencer mansion so how come the day after the events of RE0 the stars team (Chris Redfield, Jill Valentine and Barry Burton etc.....) in the helicopter did not see the rubble of the facility since they were probably searching hard in the forest.

Because it was up in a mountain overlooking the spencer mansion and it was night time. They probably would have seen it during the day.

Because Chris' eyes were still adjusting from being in the dark prison cell, Jill was asleep on Chris' shoulder, Barry was admiring his gun, Rebecca was not in the helicopter due to not being in the scenario at all, and Brad was too scared to mention it.

Well yeah Crawler but i am also talking about the beggining of the remake as well.

i agree they should have stuck with the train but then again if they did the game would not be very long would it.

how far was the facility from the mansion?

You can't have an entire RE game just on a train. Also, at the beginning of RE1 it was dark as shit outside. They had to use spotlights to see anything. And Wesker was no help because he wore sunglasses at night.

How far though was the training facility from the mansion?

I would guess 1-2 miles? I have no idea. It was never confirmed.

About a 2 miles. You see it at the end of zero.

That's what I was basing my guess on.

Really so if you went to the top of the training facility you could see the spencer mansion?

"There, maybe a mile or two away and well beneath their vantage point, was a huge mansion, shrouded with trees."

From S.D. Perry's novel Zero Hour

Suprised billy and rebbecca did not think to venture to the spence mansion the moment they arrived at the training facility since it was close by.

Well they got to the traning facility via the Ecliptic Express.

Yeah but they could have liked climbed out of a window and escaped the mansion by another route.