Since your field is rough I would suggest a Sig MidStar 40. You can install an Irvine 53 which would be more than adequate power at your altitude. This engine is in the 40 size case so you don't have the weight penalty. Mid wing would be safer than a low wing (easeir to catch a wingtip on the low wing). This plane is really forgiving and still quite aerobatic. Cubs (as previously noted) can be a bit squirley. This one you do need to build as it doesn't come in ARF form.

EXCAP232