I envy you - my railguns are both finished and all I have are happy memeories!
Anyway, the only advice would be to build the trucks in tandem - that is build each assembly twice. It cuts down on assembly time, and the second time you do the step its a little easier - you know just how the parts fit.
Also, when assembling the gun carriage you may need to file the slots for the bulkheads a bit so they slide in easier. Other than these minor things I found the kit to be a VERY enjoyable and trouble free.
Look for my post K5 railgun colors, follow the second link to see my babies!
Good luck and please post some pics when you're done!
Mark