Everything works best for a left hand circuit.
The aircraft should join the circuit from the deadside by crossing the runway at the upwind end or close to that point over the upwind half of the runway.
There is no failsafe route.
While descending deadside, the pilot should have a good view of the aircraft in the circuit and on the ground departing.
In many cases it is not the departing aircraft which is the problem it is the one on final that makes a missed approach which can cause the most interesting situation.
One of the reasons for crossing at the upwind end is that everyone knows where to look to spot the aircraft.
As with the rest of VFR flying spot other aircraft and help them to spot you.
Regards,
DFC