Err. The Star Systems close to other Star Systems is what I was getting at as a hypothesis.
They don't have to be, the hyperspace thing could go either way.
And no way in hell was Luke on Dagobah for 90 days. A couple of days, tops.
Yes but there is a HUGE difference between neighboring star systems and neighboring planets. Ships traveling through hyperspace at light speed or faster makes the travel time negligible, but the hyperdrive on The Millennium Falcon was damaged and they were unable to make the jump to light speed and had to fly to Bespin at sub-light speeds. Now let's do a little math.
The fastest aircraft made by man has a maximum velocity of mock 20 (approximately 25000 km/hour).
The average distance between Earth and Mars is approximately 225million km.
Traveling at a constant velocity of mock 20, it would take a space craft approximately 92 days to reach Mars.
Our solar system has a radius of approximately 144billion km. Therefore it would take approximately 57600 hours for that same space ship, traveling at the same speed (mock 20), to reach the edge of the solar system. That's about 2400 days. Or about 86 months. Which works out to around 7 years.
So traveling from Earth to an Earth like planet in a neighboring star system would take roughly 14 years.
So assuming that The Millennium Falcon has a maximum sub-light speed velocity of mock 20, and that the distance between where Han lost the Imperial Fleet and Bespin is roughly the same as the distance between Earth and Mars, then it would have taken Han, Leia, and the rest of them about 90 days to reach Lando. And since Luke was on Dagobah for the majority of the Imperial Fleet's pursuit of the Millennium Falcon, it stands to reason that he was training with Yoda for at least 90 days.