It's been a long time but I rode 25 miles short of that distance twice the summer of 1977. Solo, unsupported training rides. On the Fuji Pro I raced. Sewup training wheels and race gearing. The bike (and me on it) did just fine. I was in very good shape and that bike, in it's race setup, was home. (I hadn't heard the term double century yet. These weren't distance attempts. First was just a 150 miler crossing the ridge in southern New Hampshire. Got long when I got thoroughly lost on the MA/NH border. Got harder when I realized I was riding past Pack Monadnock, a small mountain I'd been looking at from the top of its sister for years. Just had to go up. Second was just a loop around the city of Worcester (starting in Cambridge), staying far enough out that I wouldn't see traffic.)
The PX10 should serve you well for this if setup/fit is good and the gearing appropriate.