i wouldn't say it is knee friendly. The HQ is near Taunton Deane services / junction 26 on the M5. Note this is equidistant from the north and south coasts.
The first bit goes up over Wilvescombe to Blue Anchor. That's the seaside in the north. Ascent: a lot. Then back again: ascent, a lot. Then you get to eat stuff at the village hall. But don't hang around too long as you don't want your legs to cool off because...
...it's straight out of the hall in the other direction and up the Blackdown hills, approx 200 metre climb. I don't remember exactly how it goes around Honiton but in the seaside on the south side is visited.
There is a massive climb back up from sea level and back over the Blackdowns again
Devon/Somerset borders don't do knee friendly imho