I think the I read the story on SOL...
Plot line was about a scientist from earth who build a space ship and travelled the universe and meets different humanoid races.
Facts that I remember from the story include:
The space ship was build in a shed on a farm
Earth was seeded with "dumbed" down humans 8n the far past. He later met up with the humans with 100% mental faculties who seeded earth.
I think the scientist had 3 females with him??
Please give me the name of the book / series.