100k miles does seem high but it's been pretty widely documented around here as to the increase in award rates. It just doesn't always make sense and your dates are challenging. I booked 4 award tickets PHX to MIA during Spring Break for 60k each. That was a Saturday to Saturday trip which we were flexible on. Originally we wanted to do Saturday to the following Sunday and the rates went up to something like 90k each. What does it look like if you by chance came back on the 6th? Perhaps adding an extra night - even if it means a different hotel - could save you a bunch.
Award trip can be funny. Just recently I booked my wife on a PHX to MSN round trip for 25k miles total. Then I needed to book it again this month and it was 70k! Same days of the week just a month later. Luckily she didn't end up going so I was able to cancel the 70k mile trip and not take that hit!