Mostly you can ride whatever you want with minimal wait.
We have always done shorter wait rides in the afternoon, and/or between G+ passes. just that is always our norm. Afternoon is a great time to see Philarmagic and Country Bears for some AC.
Tron and 7DMT are good rides to hit during the PM hours, but you can get BG for both the daytime and extra PM hours for Tron. (Assuming no policy changes and MK is your daytime park.) Someone else recently posted that they were not able to get the PM BG for Tron. I don't know if this is true, but supposedly, you can only get the PM BG if you have entered MK. You ca hop into MK, but you have to go there before 6pm. AGAIN - i have not verified that, and DO NOT KNOW if it is true, it was just reported by another forum member as an explanation for why they could not get a PM BG.
We got a PM BG for GoG on the Epcot night, but our BG was actually called BEFORE 9pm. I imagine that can happen with Tron too, only Tron is STRICT about adhering to the BG time windows. Our daytime Tron BG was called earlier than
MDE predicted.
One other IMPORTANT caveat- summer storms are common at WDW. During storms, all the WDW coasters stop running. If you wait until the PM, and there is a storm, you might not get to ride. Tings that close during thunderstorms: all outdoor boats, all outdoor coasters, all animal attractions, all outdoor water rides/pools (Kali), (so most of AK), and all outdoor spinners (Dumbo, etc). It does NOT have to be an active storm either, just lightning reported within a certain distance of WDW. Sometimes it has been perfectly sunny at WDW when they've shut down on us.
the other caveat is that the PM hours are great when they work out but only if you feel up to being out that late. Oh, also there is almost NO FOOD options at that hour. One night, we ended up getting carryout from Miller's Ale House, but we had a car. Miller's is close to WDW, one of the few places open late w/carry out. Otherwise, it is just basic pub food.
