I would post on the Dallas forum and one of the locals should be able to help.

You could certainly walk the plaza in the evening as it is an open public area, you just couldn't visit the excellent museum at the book depository.

At most a couple of blocks.

The plaza itself is free to walk around. Same with the monument built in remembrance of JFK. The 6th floor library museum has a fee but you can find a groupon or living social for it. everything is in walking distance to each other as well. Hope you get a chance to go!

I don't know I would check on line.

The Sixth Floor Museum Wesite will have an answer regarding hours of operation. Plus much more information.

Dealey Plaza is a road so is always open, the Museum/book depositary will have its opening hours on their website....hours probably differ through Summer/Winter.

I haven't stayed in the downtown in some time, however, my choice would be the Aloft. I've stayed at the Aloft in another area of Dallas and was very pleased. Nice amenities, pet friendly, and I see that there is one only 10 minute walk from the Plaza area. Downtown is very quiet on the weekends, but that can also be a plus! Enjoy your travels!

Nothing in the Plaza itself other than a gift shop where snacks, water and the like can be purchased. There are numerous places to eat within a 5 or so minute walk.