I found a gem!

OpenTopoMap is the best free mapping service for hiking and cycling that I have found, but it gives no indication of whether a path is a right-of-way. In contrast UK Ordnance Survey maps do show right-of-ways e.g. here and I include an excerpt below for comparison, moreover this site is devoted to showing them. 

My track 12.6 miles

The gem, in OpenTopoMap

Same area in Ordnance Survey 1:25000

So, I headed north along the Tiverton Parkway cycle route and found the entrance to the "gem" between the station car park and the small pond.  This path is omitted on the Ordnance Survey and FPM maps because it is a "permissive path" and not a right-of-way, and yet the land owners have done an amazing job: lush cut grass underfoot, occasional areas with picnic tables, and appropriate well maintained fencing and gates.

Check out my photos below. Click on any of the images to zoom in. 

Note the GWR up and down trains passing...

...in the near distance

No, I didn't ingest any without relizing (sic) it!

This right-of-way crossed someone's garden

I followed this typical Devon road

View from highest point

 And on the way back I checked out that elusive footpath at Whitnage.

The good and the not so good

OK, I know this will be boring unless you happen to like barefoot running and happen to be in the area and happen to want a route recommendation. Or maybe I should set up a public database of barefoot friendly footpaths.

Day 1, about 10 miles

My first foray on this trip to Devon was to explore some promising looking footpaths I had noted during our previous visit. But they turned out to be not so good - through recently strimmed brambles, fields sown with wheat, and inquisitive cows.

Day 2, another 10 miles

After a day's rest, the footpaths in my second foray were very good. The footpath part of the run is shown in the detail below.

Day 2 detail

It starts just north of the village of Uplowman (lower left of the map). The name sounds strange until you realise that Lowman is a river, and Uplowman is located in its upper reaches.

The path follows the river (technically a tributary to the Lowman, and just a brook) valley and is carpeted with soft meadow grass.  But about here it started to rain. Running in rain is very pleasurable provided one keeps warm - and I had checked that the forecast was OK in that respect.

By now it was raining steadily and I worried for my Pixel 2, as the plastic bag "sock" I had grabbed wasn't quite long enough to cover its entirety. But it survived.  At Murley farm I misread the map a bit (by now it was raining heavily, making it hard to read the map) but soon figured out my mistake.

Here I am looking back at the misty rain-sodden horizon as I climb out of the river valley towards Whitnage farm where again I lost my bearings (by now the rain was sluicing, so that I had to pause in the shelter of a barn to read my map). Those cows were content to leave me be, BTW. I decided to ignore the last planned footpath and get back home a.s.a.p. before dying of hypothermia.

Finally back along the Tiverton Parkway cycle track where I passed the 15:30 up train from Exeter to London Paddington. Thence back home to a shower and cuppa and later an excellent meal of risotto à la Instant Pot thankyou Ali!

Definitely worth repeating, both the meal and the run!