Aloha from Hawaii Bruce!
I use Sony Vegas on my laptop all the time.. and in my experience (I am by no way an expert or anything at all) Sony Vegas rarely uses the GPU except for some 3d rendering type stuff if it’s available…
I’d focus on getting the CPU power and memory to be high…
for my laptop, i’m using a quad core 2.3 ghz with 4 gig of ram and have no problems, just long render times…
If I were in your situation, I’d do the active edit’s (where you’re doing the work of editing and setting things) then save it and let it render over night… That’s what I always do for my edits if I can… If you have a powerful enough laptop though, it wouldn’t have any problems…
I’d still focus on the CPU and memory, gpu (for a laptop) is less important.. now, being that you are going to be using color correction and such, you do want a gpu that can make the adjustments you want so things look right on your screen, so that’s what I’d focus on for the gpu…
Good luck!
–James