I have got ThinkPad T400 with coreboot and minimal OpenBSD installation with full-disk encryption. All non-Tor traffic is dropped by pf. Only allowed traffic on the host is torified traffic from package manager, gpg, git and traffic from virtual machines. I set up Whonix-Workstation inside virtual machine and Whonix-Gateway on separate device. ThinkPad works without battery on AC power. I use open-hardware router. Is it a good setup for anonymous using internet?
As far as it goes it sound good.
Make sure that you follow the projects recommendations for browser settings. There are also various add-ons that can both increase anonymity and make the browser more useful.
If you install any other software, make sure that you have done a search on the "make and model" to verify that it has not been hacked. To be truthful I would not add any software that has not been vetted by the project in some manner.