This is a question from the Marlboro outwit the west challenge.  They
say in their answer pack that the questions have clues within them to
help find the correct answer.  I have researched the conestoga wagon,
prairie schooner, wind wagon, the terraqueous machine, ferry,
steamboat and boatwagon by Lew Harris.  However, I have not been able
to find anything else, and none of these seem to match like all
of the other answers I've found have (all of the rest had plenty of
different websites that you could verify with).  I'm probably
overlooking something obvious or thinking too much into it.  Even so,
I need some fresh eyes and someone who is more skilled at searching.
Here's the answer:
"For most, going west meant traveling by both wagon and boat.  But who
was the guy who figured out how to do both at once?"

Hi mama04,

I believe the guy who figured out how to do both at once was John
Mohler Studebaker who created the Prairie Schooner. Read this:

"The covered wagon that became such an important part of this
country's westward movement was invented by John Mohler Studebaker (of
Studebaker Brothers Wagon Company). Studebaker realized that families
moving west needed to travel across both land and water, and no wagons
had been designed specificially for water use. So with a combination
of his previous business and engineering experience, he created the
Prarie Schooner. Based on the popular Conestoga Wagon, the Prarie
Schooner was the first wagon to be completely water-worthy and helped
countless families safely navigate dangerous waterways..."

http://www.fairfieldhistoricalsociety.info/

Let me know if you feel this is enough verification and I will post it
as an official answer.

Best regards,
Rainbow

I've done research on the prairie schooner too, but I've found
numerous sites that refer to it as a nickname and said that it was
just a smaller version of the conestoga.  Plus, if you read further
down that paragraph, it says they have been around since the 1700's. 
In the clue it says for most going west they had to go by both wagon
and boat.  Most pioneers used the priaire schooner to settle the west.
 That's why this choice doesnt fit.  Thanks for trying though!