Butch,
That depends on how you want to design parts for your handibot. You'll definitely want the ability to use a mouse sometimes for the really detailed stuff. vCarve is not very graphics intensive and will run on any computer you could buy today. Fusion 360 (for high end 3D modelling) will put a little more load on your system...it is doing much of its work in the cloud though so it shouldn't require a high end graphics processor. I personally use a Dell with an i5 processor and whatever intel integrated graphics came with the computer and things work fine for me.
Unfortunately I haven't used a table for design...running the handibot from a tablet on the other hand will be simple. I use my phone mostly for running my tool after sending the jobs to the tool's memory from my design workstation.