Well, here's the thing:

It's been thirty years now - in real life - since Hamill, Ford and Fisher shot Return of the Jedi in 1982 (for an '83 release date).

In the EU, they're now up to 40 years after the events of ROTJ, but there's also a big gap of time between 26 and 31 years after ROTJ (the period of rebuilding after the Yuuzhan Vong War). They could easily set the new trilogy in that timeframe.

Either do that, or they could set it after the 40 year mark, age up the big three with makeup and let the EU authors know the premise of Episode VII so they can "build up" to it over the next couple years. That would be the smartest strategy, honestly.

It's also a question of what this new trilogy is gonna be about. They could make it have nothing to do with anything we've seen before if they wanted to. The possibility's are endless. I hope they don't box themselves in with the story just because they feel like they have to make certain "connections" to the other movies.