how to test the vanilla kernel

Hi Gurus, I have virtual m/c with ubuntu linux-kernel 3.2.xx. Suppose I made any fix in latest kernel say 3.16-rcx and want to test those changes. How i should go about it? I am thinking to compile the modified kernel 3.16-rcx and install it like standard procedure (make, make modules, make modules_install, make install) and boot the ubuntu in runlevl=3, to avoid GUI as it may not work with latest vanilla kernel and test kernel with existing root filesystem. Is it the right approach or need to create separate boot partition and root filesystem? If not please let me know the right way to test kernel. my host config x-86 core i5. thanks in advance, shubham