FAM is a great alt-history series. I took me all series 1 to get into it but I was sold seeing the second series. Loved the character development and the 00's technology placed in the 80's.
I don't really build fictional stuff any more but I can imagine there's interest in a model of Jamestown. You could try and relocate the thread to the
Alternate Dimensions section here, this section is more dedicated to real space. And I also can suggest taking a look at the NasaSpaceFlight forum, in the section Entertainment.
They do have a large thread concerning FAM. Knowing them, they will go all nerdy on which engines are stuck against the hull and the way it might have been sent to the moon. And then there's
the FAM wiki.
Hope you will get all the stuff you need. Remember, it is SF and they kept the imagery quite hazy and short for a reason. So you can take your liberties with it. There are no exact measurements (-;