(Edit: I see fender1 and azorch were both hitting "submit" while I was typing)

Also you could consider a 1970s sport-touring frame, like a Raleigh Super Course, or any number of Japanese frames from that era.

My '72 SC, for instance, is 531 tubing with long chain stays and fairly slack geometry which makes it comfy all day. It has long reach centerpull brakes that make the conversion from 27" to 700c rims utterly painless. And since the frame is designed for the 27" wheels, you get tons of room for fenders when you go to 700c, and its plenty wide to fit 32mm tires and wider. A Super Course can be had cheap too, if you keep looking around; there are a lot of them out there.

The only disadvantage is no water bottle braze ons and only one set of fender/rack braze ons, so you have to double up on those if you want both fenders and racks.



Photo below shows the bike is obviously not currently set up for rando work, but gives you an idea of geometry and fender clearance: