You may want to combine a walk a walk with a stop at a castle or other historic location, or just go and visit. If so and you are over 60 and living in Wales then CADW currently offer a pass for free visits to all their properties. Ours lasts until 2019.
However, entry to this scheme stops at the end of May this year. Contact CADW for an application form if you want to squeeze in before the portcullis drops.
Dave