We started looking at colleges after sophomore year for our D. We went to visit big, small, private, public, urban, rural, religious, hands on, theoretical, etc… You are fortunate that there are a lot of schools in the MD/DC/VA area where you can easily visit and see what appeals most to your son. Then he can start narrowing down on a list.
I will also say that I thought my D would do better at a medium sized school but Purdue was her #1 after visiting 15 schools. She proved us wrong and had an amazing experience (and yes she was in honors but her non honors friends still had the access to research, projects, and close relationship with professors). It’s all about fit!