I replaced my left hand rad a couple of years back and found the job not very difficult. The front bumper as well as the wheel liners must be removed to get at the rad, fan, electrical and hoses. Having the front raised helps in minimizing coolant loss but at your milage and water pump issues you will likely replace all the fluid anyway. It is also likely at that age & milage that some of your hoses may need replacing as well. It is also a great time to clean all the crap from the rads and A/C rad.
There are a few videos out there showing the process and here are a couple covering 996 that is the same on the Boxster.
https://www.youtube.com/watch?v=TVPZdGiiw40
https://www.youtube.com/watch?v=ACLaRKjbf5o
Good luck!