[crystalzapdos]

Okay, I'm going to attempt this. The only thing that is outright said in the game is:

FR/LG---3 years--->HG/SS.
B/W---2 years--->B/W2

After that, theres a news report of the Red Gyrados at the beginning of Platinum, so this makes it:

FR/LG---3 years--->HG/SS-D/P/Pt.
B/W---2 years--->B/W2

Most people believe that R/S/E takes place at the same time as FR/LG because of the Sevii Islands quest, but I personally disagree. I think that it was just because they had to make a way to trade with R/S/E, so I personally think that R/S/E is open to speculation. However, in B/W2, there's two Aqua and Magma grunts who say that many years ago, They had a battle to expand the land/sea. They have a family, so they had to have time to settle down. Also, the Rocket member in B/W also had to settle down and had kids, so this confirms B/W comes last. This basically means that R/S/E is anywhere before B/W, so that leaves us with three possible timelines.

R/S/E---???--->FR/LG---3years--->HG/SS-D/P/Pt---???--->B/W---2 years--->B/W2

or

FR/LG---3years--->HG/SS-D/P/Pt---???--->R/S/E---???--->B/W---2 years--->B/W2

or

The FR/LG Sevii Quest theory is true, making it:
R/S/E-FR/LG---3years--->HG/SS-D/P/Pt---???--->B/W---2 years--->B/W2

Personally, I believe in the second timeline. I think the world tournament is non-cannon and completely ignores the timeline.