Off the top of my head, I think ~49 miles is my longest.
I was doing general flying in our ASW-28 "OH", we had issues with the electrics (nav, radio's, etc.) but I had an analog vario and could look outside.
At one point, I managed to get a text off to my son (since the radio worked about 500'...)stating where I was and where I was headed (he was at the home airport) so at least they had a clue where to look at some point if need be.
I ended up over the Delaware water gap (at the NJ/PA border)and did my final climb (late in the day) over a forest fire to ~8500' MSL (home is ~520' MSL).
I turned towards home, did some "rough calculations" in my head and thought, "I'm basically final glide home, unless I hit sink."
I set a cruise speed a bit over best glide, set the trim & watched the terrain slide by at a rather slow pace.
When I was a few miles out, and was SURE I had the airport made, I sped up a bit..... landing long after anyone else that went away from the airport.

While I hit a "few bumps" on the way home, it was pretty flat. At least most of the terrain was landable with no issues..... if needed.