>>/30886/
> I guess a few km long power cord would be inconvenient.
Quite.
I would figure that lighter would be better in the way that a canoe made of balsa wood, would be better than one made of steel. While I've read mentions about them having some 10mm thick plating, that seems a bit excessive. However those estimates are likely for the more "universal" (lol) types of crafts which can go to the moon and inner earth and not break a sweat.
Currently a saucer attack craft is beyond the scope of this discussion. So I see no need for it to be beefy as a cow.
https://www.warp-drive-physics.com/
Check out this site, it has quite a bit of information, so much so that I'm having trouble justifying spending a few hours to sift through it, let alone understand it.
As for basics there are some resources available, at least enough to figure up an engine. Any further avionics would be solely up to you to figure out (ie system monitors, controls/control surfaces, visual systems, emergency systems, etc) But that shouldn't be too hard if your able to at least build the core component of the whole thing.