I'm not an experienced tourist, and I think that's optimistic. The greatest distance I've ridden in one day was 165 miles, on a racing bike with no cargo, and it left me shattered, even after training up to it from a pretty good baseline of fitness. Actually I was shattered around mile 120, and just hated life the rest of the way. You know when you're too whipped to unweight the saddle before riding over a bump, and it just thuds into your butt? Like that.

You're talking about doing almost the same distance repeatedly, on a hybrid with one un-aerodynamic hand position, carrying a modest amount of cargo. I actually like the idea of touring as a form of physical challenge, but I see no reason to extend that into the hating-life zone.