Stephen McGregor from Hannibal, MO on 7/9/2018 3:29:31 PM:
I rode it with Clement XPLOR USH 700x35's and wish they'd have been a little bigger, but bigger wouldn't fit in the fork of my Gravel Bike. The surface isn't really compacted (by the Katy Trail Standards). My friend rode her mountain bike with Scwalbe Marathons (I think they were 42m and had the puncture resistant liner), and she had some trouble around Newport, where the sub irrigated soil and loose gravel gave her a good spill.
You can probably ride on your tires, but it's not anywhere near a hard surface trail.