Oh TheUnlogicalOne! I love it!
The laser turret has a beam expander behind a conformal window and everything! There's a radiator, and most of the ship is propellant. You seem to have gotten it all correct.
RTGs do not have much in the way of radiation shielding requirements. For most nuclear RTG fuels you can get away with as little as 25 mm of lead shielding. And if you use Plutonium-238 as fuel, you'd only need 2.5 mm of lead. In some cases the RTG case would provide enough shielding.
The trouble with RTGs is that for certain technical reasons, the maximum you are going to get out of a single RTG is one kilowatt. You can stock as many RTGs as you want, with the restriction that each one will mass about 100 to 200 kilograms.
Off the top of my head I think the only things you need to add are a habitat module and a few antenna. As you know a habitat module is generally either spherical or tank-shaped. A Bigelow style inflatable module is good if mass is at a premium, otherwise a metal one. Maybe with a navigational astrodome.
Atomic Rocket: Beginning Design Atomic Rocket: Decks: Astrogation
Hydrogen is the best propellant for a solid core nuclear thermal rocket. You've already got a bimodal NTR. Maybe a small oxygen tank if you want to add a LANTR afterburner.