Going on a long arduous journey in train primarily with Reginald taking in weekend with family (8)
I believe the answer is:
trekking
'going' is the definition.
(thesaurus)
'long arduous journey in train primarily with reginald taking in weekend with family' is the wordplay.
I cannot quite understand how this works, but
'arduous' could be 'trek' (I've seen this in another clue) and 'trek' is found within the answer.
'in' is present in the answer.
'weekend' could be 'k' (I've seen this in other clues) and 'k' is found within the answer.
A single letter 'g' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'on a' acts as a link.
Can you help me to learn more?
(Other definitions for trekking that I've seen before include "Arduous on-foot activity" , "Backpacking" , "Making a long difficult journey" , "Walking holiday: migrating by Boers" , "Arduous walking" .)