If you can, I recommend an ice machine. I've used both ice packs and the machine for past surgeries, and the ice machine is much better than ice packs. Just make sure not to get one that has a 30 minute timer-I can't imagine getting up every 30 minutes to re-start the dang thing. Some with timers do have a continuous setting also-just double check.
If an ice machine is not possible, I'd suggest at least 4-6 sets of ice packs-you'll need two at a time if they don't wrap around your knee fully-and you want to make sure to always have some frozen and ready to go. I made my own in the past so as to have them custom sized, plus I sewed cases for them with two different fabrics. One side was a little thicker for when they first came out of the freezer and were icy cold, the other side was a little thinner to flip over as the packs got warmer. I also used velcro to close the end so the ice packs didn't slip out. I'd suggest trying the packs before your surgery to see how fast they defrost and warm, how fast your freezer freezes them, etc, so as to really know how many you'll need. I iced almost around the clock at first as it really helps to ice your knee a lot after knee surgery. I also suggest some kind of wrap to hold the ice packs on your knee as they will constantly slip off if they're not attached. It drove me nuts to have to keep trying to re-situate the dang things.
If you can, I also recommend a Lounge Doctor to elevate your knee-I've used pillows in the past and while they work sort-of, the LD is a ton better.
I used a walker for a few weeks so had a folding cup holder on it and also a walker bag to carry items around when my hands were not free. I made sure to set up my recovery area with easy to eat snacks, TV and fan remotes, and a dedicated side table for odds and ends to supplement my nightstand.
With my first TKR, I had low toilets and really needed to use the bedside commode over the toilet; with the last one we had replaced the toilet with a comfort height toilet so I didn't need the commode. Try to get up and down on your current toilet with your surgical knee straight out in front of you and using just your arms to get up and down and see if you can easily do it. After surgery it'll be harder, so if it's hard now, it'll be much harder later, so I'd suggest a toilet riser of some kind. Good luck and keep us posted!