Journey time appears to be the same:If I put in the journey I did today Rye to Ivybridge for next Sat- Southeastern's website comes up with the obvious route via St Pancras and Paddington. Trains can be cheaper uses the same super off peak fare but sends me via Brighton, Clapham Junction, Exeter St D. taking much longer I can't work out why.
http://www.fastjp.com/#journeys?orig=RYE&dest=IVY&odate=20170408&otime=1000&maxres=10&maxch=3
Rye 0956
Ashford Intl 1018
Ashford Intl 1038
London Victoria 1207
London Paddington 1300
Newton Abbot 1555
Newton Abbot 1623
Ivybridge 1652
vsAshford Intl 1018
Ashford Intl 1038
London Victoria 1207
London Paddington 1300
Newton Abbot 1555
Newton Abbot 1623
Ivybridge 1652
http://www.fastjp.com/#journeys?ori...:&odate=20170408&otime=0955&maxres=10&maxch=3
Rye 0956
Ashford Intl 1018
Ashford Intl 1043
London St Pancras 1121
London Paddington 1300
Newton Abbot 1555
Newton Abbot 1623
Ivybridge 1652
However I agree that going via St Pancras is preferable as you have longer to cross London, and a greater frequency of through LU trains for the transfer.Ashford Intl 1018
Ashford Intl 1043
London St Pancras 1121
London Paddington 1300
Newton Abbot 1555
Newton Abbot 1623
Ivybridge 1652
If you specify via: St Pancras, then itineraries via St Pancras are shown.