Having done this one way just over 2 weeks ago (with a more detailed report!), I decided to try the out and back - unsupported.
An early start, mainly to beat the high tide that makes a couple of sections virtually impassable, but also to try and beat the heat.
Set off about 90 mins before low tide, beach areas were a bit soggy still, tho fine on the way back. Was unpleasantly surprised how much the brambles, nettles and grasses had grown in the 2 weeks since I did this route, really tough going for a couple of sections, twice of course (out and back).
Enjoyable first half, despite a couple of stops to sort out my equipment, water belt kept slipping as I carried a lot more water than normal. As it turned out, still not enough, as though the sun was behind the early morning clouds until halfway, the humidity was ridiculous. That, and dropping my last water bottle as I was trying to drink it’s contents, meant I had to do the last 6 miles with no water - a run-walk strategy that ended up being a walk-walk strategy at the end!
The Billy Line was in good condition, despite their being a race the previous evening, and unusually quiet, just a few dog walkers and a couple of runners going the opposite way. The Eastern Road still needs a minor diversion due to the ongoing sea defences work, but otherwise I was able to keep to the route.
If I did this again, would definitely pick Spring or Autumn to avoid the heat and worst of the vegetation on the pathways. To confirm, run was done unsupported, carrying my own water and energy gels.