Upcoming Trip, Spontaneous or Planned?

I'm going for a one week trip to Orlando in about a month with my mom (she has a timeshare off-property, near Disney Springs).

She thinks we can buy tickets to MK and Epcot a couple days beforehand. No dining reservations either, she wants to be spontaneous, because that's how she did our trips 10-20 years ago. (The only reservations I was thinking about were Raglan Road and Homecomin in DS)

Just wondering how practical spontaneity is nowadays? I'm a pretty big planner so I've already done a ton of research. I know what rides and restaurants I want to do, but is it ok without reserving tickets until a couple days before?