So I ran some of the numbers based off of the usfirst.org 2014 directory.
FiM has .005662 teams per Sq Mile
MAR has .003164 teams per Sq Mile
PNW has 0.001237 teams per Sq. Mile
NE has 0.003302 teams per Sq Mile
Indiana has 0.01758 teams per Sq Mile
FiM has 21.9 teams per event
MAR has 24.4 teams per event
PNW has 20.1 teams per event
NE has 23.0 teams per event
If I were to guess, I would say that Indiana will have 3 district events. This would be 21.0 teams per event, keeping it in line with the other regions.
Also, MAR is weird because land area in not easily accessible for Eastern PA, so I used all of PA. This was also true for finding teams in PA, so I just used all of PA teams. I also included the 1 regional in PA, making the "event" count for MAR 7. This may be why MAR's teams per event is slightly higher than other regions. PNW's teams per Sq Mile is so low because both of those states are huge, while Indiana's is so small because there are only 63 teams.
Link to data here:
https://docs.google.com/spreadsheets...it?usp=sharing