Assuming you go all the way and win the championship, with home court you will be making more than normal (2/3 + 2/3 regular arena income) through the first two playoff games, and no worse than normal (2/3 + 1/3) in the finals, so you really only have to weather one week of no income: between the end of the finals and the start of the new season. And the 100k promotion bonus is about the same as your arena income, so it's really like you will have NO weeks without your usual income.
Given than you can go up to -500k in debt without really having to worry, you should not have to worry :)