Where are there any high elevations east of the Mississippi? The highest mountain is lower than the streets of Denver.
That aside, Cherry Hill is not the only CG in the DC area. Fairfax County Park is just outside the beltway, not far from the Metro where there is parking & at about $45 a whole lot less than Cherry Hill. Quiet too. No highway noise.
Go a little further out of town for Bull Run Regional Park near Manassas. Close to the Manassas battlefield &, if aviation is an interest, the best aviation museum in the country IMO at the south end of Dulles International. Amoung other things it has the last shuttle, a concord & the Enola Gay.