Mercersburg has a great orientation that takes place a few days before classes start. New students arrive first, and are assigned to peer groups with other new students. Each peer group has 2 peer group leaders who are upperclassmen / women. Peer groups then meet every week during one evening each week until mid February. My son was a peer group leader this year and really enjoyed his experience.
There are plenty of high stat kids at Mercersburg who thrive and challenge themselves there. Courses are offered on every level, so surely you can find what you are looking for in terms of academics.
Mercersburg is rural, but my son has never complained about the location. There are many activities on campus during the weekends, and the campus does not empty out on the weekends. Days students are about 15% of the population, with many of them being children of faculty and staff. We have always found the community to be friendly and welcoming.
If you need to fly to get there, then Mercersburg is further from the airport than L’ville will be to Philly airport.
Congratulations on having two great options!