Writer’s trip by wagon taking in grand prison like Alcatraz? (9,3)

'alcatraz?' is the definition.
Both the answer and definition are singular nouns.
Perhaps they are linked in a way I don't understand?

'writer's trip by wagon taking in grand prison' is the wordplay.
I cannot really see how this works, but
'wagon' could be 'cart' (cart is a kind of wagon) and 'cart' is located in the answer.
'grand' could be 'g' (G is short for grand as in a thousand) and 'g' is found within the answer.
'trip' could be 'ride' (eg a trip in a car) and 'ride' is found in the leftover letters.
'prison' could be 'pen' (both can mean an enclosure) and 'pen' is found in the answer.
No letters remain.
This explanation may well be incorrect...

'like' acts as a link.

Can you help me to learn more?