Small wedding... big families... help!

Hi! We got engaged about a month ago and are having a hard time deciding on what to do!
We both agree we want something small and simple. We don’t want to spend thousands and thousands of dollars on a wedding. It’s also important to us to get married in the church. We would elope if it wasn’t for the church (and the fact that our families would probably kill us!).
So our dilemma now is that we both have large families. We were able to get a list of immediate family, aunts and uncles and very small number of our closest friends to 65 (the number of people the chapel we found will hold). We were thinking about having the wedding on a Friday and then having a bigger party that weekend to celebrate with everyone (extended family and friends).
Any ideas on what we can do after the wedding ceremony? I know we need to do something, but this is where I’m stuck. It’s too large of a number to do a dinner without it costing as much as a formal reception!