Welcome to the area.
I echo Bob comments on Tim's a pretty good shop and they have been very nice when I went there.
Entertrainment Junction near Westchester (Up 75) has a nice hobby shop(and a great indoor layout to visit), mostly G and HO but some good scenery stuff.
https://entertrainmentjunction.com/
HobbytownUSA in Mason has a good supply of scenery items, and some O scale, but mostly HO and N. Good supply of paints and scratch building supplies.
https://www.hobbytown.com/cincinnati-oh/l88
There is a modular club Queen City Hi Railers, they have a permanent location with a fixed layout, and the portable modular one as well.
http://www.queencityhirailers.org/