1. Widecombe. An old town of Devon, Dartmoor. Spelling sometimes Widdecombe. Inspiration for the jolly rouser about Uncle Tom Cobley and all, perhaps on the gray mare at the Widecombe Fair, see https://www.youtube.com/watch?v=16chelA5pTc. There is apparently a traditional Saxon Well nearby; the area was a Saxon administrative center centuries ago, see http://www.moorlander.co.uk/about_dartmoor.html.
The area's inhabitants resisted William the Conqueror in his push westward, requiring William to build several castles (not seen by us) to establish his domains.
2. Saxons. Where is the research about them in particular, not just the Domesday or general Old English ideas?
Our understanding is that Saxons arrived along with or not long after the first Angles, when the Romans left. See http://historymedren.about.com/od/sterms/g/Saxons.htm. Angles and Saxons intermarried apparently, or at least did not severely conflict with each other, and voila, Anglo-Saxons. The royal mints for Saxon Kings Ethelred, Harald, Edward, were located at Dartmoor. See Moorlander. Widecombe-in-the-Moor: a topic of great tomes, see this 1865 Google Book, Western Antiquary. There was an Anglo-Saxon settlement at Dunstone, see http://www.widecombe-in-the-moor.com/about.php, and the word root dun itself as Saxon, see http://dictionary.reference.com/browse/dun
3. Venture farther back than Saxons already in the British Isles. Move to their own source, many in Saxony.
In Saxony, pursue a famous chieftain of the Saxons, Widukind, who harried Charlemagne for some 30 years before forced to capitulate, as he did in part. See Germany Road Ways, http://germanyroadways.blogspot.com/2010/12/enger-widukind-saxon-bane-of.html. A church dedicated to him, and containing bones said to be his (no comparative DNA?) behind the altar are at Enger, Germany. See http://germanyroadways.blogspot.com/2010/12/enger-sudden-saint-widukind-and-church.html.
The fine statue of Widukind at Enger, a pride of the town, was melted by the Nazis for war materiel.
Some spellings, some phonetics, are so close as to suggest a connection between otherwise separate-looking ideas, places, histories. After finding Widicombe Fair in an old piano book of folksongs, listen to it at youtube again, above, and then think of the Saxons, some migrating peaceably to the British Isles in the course of things; others forced out by Charlemagne after Sachsenhain's slaughter, numbers may vary but the impact on the population did not, see http://germanyroadways.blogspot.com/2011/02/sachsenhain-saxons-grove-charlemagnes.html
4. Widukind's folk to Widecombe?
Saxon Widukind's kin to live on, in a way, in Dartmoor? That is up to the venerables on the moor: can you check for us? The root "wid" also is of Scandinavian-Saxon origin, do a search on Google Images for Runes Widing for an example of an amateur etymological sleuth enjoying life, and matching an old family story with old runes. WID.
Runes. Here experts are needed. Our look into runes WID and runes produces fun, but little to withstand a serious researcher on the root wid, as it is also found in old incantations. See http://swedenroadways.blogspot.com/2010/07/anglo-saxon-runes-ingwaz-moves-widing.html
The surprise is finding so little about Saxon roots in the Dartmoor materials. Spur on. Inform us all. Please.