I took a slightly different route (and in the reverse direction of your plan) when I walked out from Inshore bothy last March.
On my route recorded below, there is a very faint path from leaving the cape road right to where I dropped down to the shoreline, the drop down is on a very prominent quad track, the walk along the shore is easy though and quite nice, on one occasion last year I got across the burn about 800 yds before the wee foot bridge (tide and river were very low) so saved me a bit.
The routes posted a few posts up, I've also followed but i cut between the 241 point and beinn an amair and then dropped down to the bridge further along the cape road, it was ok, a bit drier underfoot than the lower route, although it was later in the year.
Both routes were easy enough, but some very very wet patches.
Joint warrior could be a drama, I'm not sure of next years dates and I also got caught out by a last minute bombing ex that wasn't in the forecast.