No, old thing, not in riotous dissipation. No such luck! The cost of living ordinary plain, or garden living nowadays is, I assure you, if you do not know   
The narrator is talking about the cost of living.
The narrator does not care about cost of living at all.
There are mostly public institutions.
These people are all dressed.
A dog is running.
Bicycle racers are being cheered on by everyone in a large crowd.
A boy goes kayaking.
The people are outdoors.