Most of the Lincolnshire Wolds has been designated an Area of Outstanding Natural Beauty (AONB) and it is a wonderful area of countryside with some of the most beautiful, unspoilt scenery in the East Midlands. https://www.lincswolds.org.uk/exploring/walking/ provides a link to a selection of walks – Gateway Walks which are walks on the edge of the Lincolnshire Wolds near the towns of Horncastle, Market Rasen, Spilsby and Caistor; and Wolds Walks which are a selection of walks in the Wolds.
https://www.visitlincolnshire.com/things-to-do/walking/wolds-walks/ and https://lovelincolnshirewolds.com/routes provide further links to some walks in the Wolds.