I'd suggest renting the ecv from an offsite rental place for your entire trip. You would be walking miles every day in the park.
The ecv will take you where ever you want, both in the parks and outside the parks (resorts, to and from bus stops to the parks, or your resort room).
Offsite ecv will be well worth it at the end of the night and your knee hurts like heck. Just be sure to follow signs, some rides you take a detour when it gets close to boarding a ride, sometimes you follow the same route as people walking.
If you need ice. Stop by the first aide station. I rent an ecv and sometimes i've walked to much and didn't bring my ice pack so head there if need be.
They have those old fashion ice packs/hot water bag holders you can buy at a large grocery store, a place like target or the like. . The ones i have are white with blue stars on them. If you like to ice a lot, just ask for
cups of ice at the counter service places and fill up the bag. Much less messy than ziplock bags.
If you rent a fridge or if you are staying at a mod or delux you have a fridge in your room.
I do the ice massage in the mornings and at night to combat swelling, soreness. Basically you take a dixie cup (foam or paper). At disney we fill it with cold water and ice. Takes about 24-48 hours to freeze in the little freezer section. Then use that. If you don't know how to do an ice massage ask you doc or pt for instruction. You don't want to accidentily freeze your skin and cause more damage.
If you have some type of nsaid, or pain pills, bring them with you into the park. They won't do you any good when you hit some pain and they are sitting next to your bed. Bring fanny pack, back pack or something else to keep it in, and put them in a ziplock to avoid them getting wet or coming out of the bottle for an unknown reason. I try to avoid the pain/nsaid meds due to stomach problems, so thats why i like the ice. But, i've heard the people next to me complain they forgot to take their xxx when they left the room, and their knee hurt like heck.
Hope you have a fun trip!
Connie