One of the largest National Parks in the UK is in Dumfries and Galloway. Uncharacteristically, you can get a Highland Experience in the Lowlands - if you hike up many of the hills in the Park. This contrasts greatly from the usual D&G scenery (which is mostly just coast and farm-land).
The pictures below are from the south-side of the park. Some of the peaks include Muldonnoch, Curleywee, Cambrick Hill and Lamanchan Hill.