Ronnie's message to Imogen is
IMOGEN IN LOVING BLISS
COVETING A GENTLE KISS
COMPLEMENTING ME IN LIFE
PLEASE BE TO ME A LOVING WIFE
Because
The board game involved is Monopoly. Starting at the space "Go", you have to read the first letter of the current monopoly space after performing the next dice rolls (if you roll dupes, you are allowed to roll again without staying on the space in monopoly).
The words in the story "dog, iron, wheelbarrow, shoes, thimble, shipped, car, hat" are all monopoly playing pieces. "monopolizing, red dice" are also additional clues. Furthermore Monopoly originated in the United States, and this puzzle only works when the solver uses the classical american board, which explains why this wouldn't happen in Europe, as there are many different versions of Monopoly worldwide.
Here's the runnable JavaScript version of what I did with OP's message as initial input.
List of all visited fieldsspaces in order:Income Tax
Marvin Gardens
Oriental Avenue
Go
Electric Company
New York Avenue
Indiana Avenue
North Carolina Avenue
Luxury Tax
Oriental Avenue
Virgina Avenue
Indiana Avenue
North Carolina Avenue
Go
Baltic Avenue
Luxury Tax
Income Tax
St. Charles Place
St. James Place
Chance
Oriental Avenue
Ventnor Avenue
Electric Company
Tennessee Avenue
Indiana Avenue
North Carolina Avenue
Go
Atlantic Avenue
Go
Electric Company
North Carolina Avenue
Tennessee Avenue
Luxury Tax
Electric Company
Kentucky Avenue
Illinois Avenue
Short Line
St. Charles Place
Community Chest
Oriental Avenue
Marvin Gardens
Pensilvania Avenue
Luxury Tax
Electric Company
Marvin Gardens
Electric Company
North Carolina Avenue
Tennessee Avenue
Indiana Avenue
North Carolina Avenue
Go
Marvin Gardens
Electric Company
Indiana Avenue
North Carolina Avenue
Luxury Tax
Income Tax
Free Parking
Electric Company
Pensilvania Railroad
Luxury Tax
Electric Company
Atlantic Avenue
Short Line
Electric Company
B&O Railroad
Electric Company
Tennessee Avenue
Oriental Avenue
Marvin Gardens
Electric Company
Atlantic Avenue
Luxury Tax
Oriental Avenue
Virgina Avenue
Indiana Avenue
North Carolina Avenue
Go
Water Works
Income Tax
Free Parking
Electric Company
