I have one that I have not installed yet (it will go on with either a fresh rack or pump). I think it's a good idea, as the decent filters are pretty cheap, bypass once plugged, and should be good for years. Otherwise it can be tough to completely flush the system, let alone trap anything from new wear.
You can get ones with a 3/8" barbed fitting, so you splice it into the return line. It would be easy to do in-line (in series) from the rack to the cooler but the filter could get hit with road debris there. I'd try to put the filter on the line from the cooler to the pump (where the filter is more out of the way).
You could also use a sandwich adapter with an Allison trans filter (for big trucks). You'd probably end up mounting the adapter in the driver side fender well, since there's lots of room up there.
Good luck.
Good luck.