Actually, @ElsieD, check them at 3 1/2 hours. You might decide they need more time dehydrating.
Also, with the peaches I did last year, I did not freeze on trays. I took the peaches off the tray, put them into a vacuum sealer bag, jiggled them a bit to get mostly the same thickness of items in the bag, sealed them, then put them in the freezer.