Which park is easiest for me to see the waterfalls. i hurt my leg and need crutches. I can still walk, i was wondering if one park is less walking to see waterfalls
Definitely Krka. You can take a boat from Skradin up to Skradinski Buk, the big cascading waterfall on the river. You can walk up the side of it a little as much as your crutches allow. In Plitvice, you will have to descend down into the park and come back up - there is n way up besides walking up, so on crutches that might be quite a challenge.
I'm sorry, I haven't been to Krka but i think Plitvice would be extremely difficult on crutches! The walkways can get narrow and wet. To descend and then to go back up it's steps that are steep and narrow. No other option to get back up. Sorry for the bad news.
I hope you have a great trip wherever you go