It sounds as though some here may not have kept up with recent Tarptent.com models. They now have several double-wall tents in which either the inner net tent or the fly can be set up separately (Moment DW, Stratospire, Notch, Scarp). What's different with their tents is that, unlike the standard offerings available at REI, the fly on the Tarptent models is set up first so the inner tent doesn't get wet when it's pouring rain. The inner tent can clip to the fly so both can be set up together, with the inner tent staying dry.

Having been in SW Ohio in the summer several times, I wouldn't even be backpacking in such circumstances. We don't have that 100% humidity out here--well, only when it's cold--and combined with heat it just lays me low. The last time I visited Ohio was mid-October, which was perfect!