I have not run in that brand but the concept is what you may be looking for. First, I would ask the PT for their recommendation as they may point you in a direction different that I will.
For running, I would look for a design similar to this 1) an open knee to prevent pushing the patella into the joint for 4-7 hours. 2) I would also look for one that has a cut out behind the knee to prevent material bunching up and rubbing the area raw. 3) While optional, I like the Velcro strapping as a regular sleeve will always feel like is falling down.
I like DonJoy products as I know the last and have a heavy ortho review.
http://www.betterbraces.com/donjoy-reaction-knee-brace - This may be heavy for a first run at 26 miles, but I used it through my injury last summer.
http://www.betterbraces.com/donjoy-performer-knee-support - This is a minimal design I would feel like I needed to pull up all the time
Though a minimal investment and really a no-harm design. (I would try this style if you can find
)
I would look for as minimal a brace as you can find. I would run on Friday or your first morning in WDW to make sure you have a feel for it. It will not feel natural. Lube the area around the patella as this will start to abrade after some time on the road.
Good Luck