But I don't think it takes 12 years
They did it simultaneously
Any chance in any of this taking place in more than one year?
I think it makes more sense for incognito to be of 1 month as the only thing which happens is Keechak Vadh, What are the chances that he didn't see Draupadi for 11 months, sees her in last month and tries to molest her?
If Arjuna can marry 3 times roam around India on horse back in 13 months, Ashvamegha and everything which happened after Kurukshetra war can happen in 36 months then why can't exile after Dice hall be of 13 months?
It can be. But exiles didn't have horses. They were wandering on foot, even crossing into.China at one point. Plus, negotiations take time. And Yudhishtira actually refuses to consider a shorter exile.
Plus, the Panchali thing is arranged by Virat's wife. Sudeshna got worried Panchali might attract the king and sent her to Keechaka on purpose. That's probably why she was spotted after 11 months of remaining hidden.
I don't know if the duration was strictly 13 months, though. Could've been shorter. But not 13 months.