Looks like I need your advice again.

On Sunday 19 August I want to travel from New Eltham to Dover Priory
arriving before 11, returning from Dover after 18:30. I'm doing Dover
Castle.

Southeastern has a £25 off-peak day return offer, see
https://www.southeasternrailway.co.u...-offers/offers

Problem is I do not want to travel if it involves replacement buses
and I do not know how to properly check for planned closures. I have
found this:
https://www.southeasternrailway.co.u...ate=2018-08-19
but I do not fully understand the information.

If I type in New Eltham to Dover Priory I get complex journeys
involving many changes,some with a yellow warning symbol. This one
does not have a warning, but the times between trains are very short,
worrying me the journey might take much longer if I miss a connection:

07:48 New Eltham
07:55 Hither Green

08:09 Hither Green
08:18 Chislehurst

08:32 Chislehurst
09:28 Ashford International

09:35 Ashford International
10:05 Dover Priory

If instead I search for London Terminals to DVP I get the 09:37 high
speed direct train form St Pancras also costing £25 off-peak day
return. Can I use that ticket to get from New Eltham to St Pancras?
If not, using PAYG it will be an extra £9 to get to and from St
Pancras.

--
jhk