The following sentences should be included in a summary of the text:
- Fitch's boats cost too much to make.
- John Fitch combined old methods of constructing boats with new technology to create the first steamboats.
These sentences effectively capture key details from the paragraph regarding John Fitch's contributions and the challenges he faced. The sentence about Robert Fulton, while relevant, is more about him than Fitch, and the opinion about riding on a steamboat is not relevant to the summary.