1991 Ford E150 Running Boards

[ChadH]

I have a 1991 Ford E150 with a 138" wheel base with the quadravan 4x4. My wife and kids struggle getting in and out. I'm looking for running boards but don't see much available for this set up. Do people generally just by truck running boards and modify the brackets or fabricate their own to fit the van or is that not necessary for install. I figure I'm going to have to do some drilling under the van but don't want to spend hundreds of dollars and end up having to make my own brackets.