For what you are describing 42mm tires are easily all I think you will need or want, so I would not worry about a bike clearing more than that. I use 38s for exactly what you are describing. My bike (Soma Fog Cutter) will clear 42s, but unless I was going to be riding strictly dirt roads and some double track, I would not bother with anything over 38.
Of course, a lot of frames that clear up to 700cx42 also clear 650bx47.
There are a ton of “gravel” bikes out there which will fit the bill. All City Space horse is one that I like a lot (a good friend of mine got one).
Last edited by Kapusta; 04-25-19 at 07:15 AM.