That would be Foxtor Mires they meant not Foxtor itself. As it stands, Your route from Whiteworks to Childes tomb goes right through the Mires anyway ?! I wouldn't advise that. Go via Nuns Cross and skirt the Mires.
You are going to have plenty of wetness underfoot on the moors nowadays.
A fair amount of cross country day one. There are paths map denoted and some not, especially near the rivers - but even marked paths on the moor can be bog hopping and intermittent and easily missed unless on the ball. Much of the range poles have well trodden 'paths' between them nowadays.
Just lifting a little now, but heavy rain forecast again overnight, weekend forecast not looking as bad as recently - grey or showers....
Fox, I'm not clear on your route , but IMO the Yealm is not worth bothering with unless have you a particular reason. It's a slog over bare hills and there are more interesting things to do with limited time!
From Childes tombe, I'd consider ignoring the bridle way on the map - as Andy says, it's not really there. So, I'd go, Fox Tor, Black Lane - posts, maybe nip to Ducks Pool, then down Blacklane Brook for some time, then off East to Red Lake Tip and Broad falls, down the Avon, then choose a route to Eastern Whittaburrow . Then Back over west to Erme Pound, back up the River Erme to Erme pits, then over to the Plym somehow.(calveslake or Plym Ford) It's really well worth going the path from Higher Hartor Tors through the Drizzlecombe stone rows and past Giants basin before heading to Sheepstor. As well as the latter, I'd also consider Combeshead or Down Tors for camping too. Then Crazywell pool, and, as personally I don't rate Cramber Tor much- so for more interest and beauty, I'd then follow the leat down to the Meavy Aqueduct and up to Black Tor . From there cross the road and join the old railway line back into Princetown.
If the weather is Good and you feel fit, , I'd seriously consider not going Kitty/West Okement at all that first day, but going down the Rattlebrook, skirt the range poles to the Amicombe/Tavy, cross, then head to Fur Tor, and either camp there, or push on to East Dart (range poles again) and camp there. Even then it's only 9 miles day one.
Then Day 2, down the East dart through Sandy Hole pass to the waterfall, contour along the old leat to drop to Grey Wethers Stone Circles, then cross the Teign by Teignhead Farm, up over Manga Hill to Watern Tor, then head to either Steeperton/Wild/Cosdon areas to camp and get great sunset views. (8-10miles)
Day 3 could go back via Cullever Steps, Row, West Mill, Yes, High willhays, drop to Lints then come back down the West Okement to cross below Black aTor Copse, (suggest weir bridge)above Vellake Corner if water high) then over to Sourton. (11.5miles max - less if avoid Lints and go straight to Black tor Copse) )
All those days can be modified to be shorter if necessary.