Consider walking up the stairs earlier than your time or on a different day. It's 700 steps. I'm thinking it takes 15-20 minutes and you can rest on Level 1. My 4 1/2 year old did it twice in one trip and insists on doing it each trip now. It will be 5€ each, kids may be cheaper. There is another line for the ride to the top on Level 2. I don't know if the ticket times matter at that point because you can, in theory, take as long as you like to get in the second line for the elevator to the top and the line can be as long as an hour. The sunset view will be great from Level 2, so don't get in line for the top and miss the sunset! Walking down from Level 2 is also an option if the elevator lines are too long.
It would also be pretty spectacular to be on the tower on the hour after dark for the "sparklings". It happens for ten minutes. Starting times are on the website. It's thousands of strobe lights so if these bother you, get to Trocadero, a bridge or Champs de Mars to observe from a distance.
If you have kids, there are two playgrounds in the vicinity. One for little kids is tucked around from the South Piller; the other is further away closer to l'École Militaire. The latter is newer and more extensive. There was also a hand-cranked manège [carousel], a pedal car track, concession and washrooms nearby in 2012. I wouldn't use the washrooms after dark, even if open. Bring toilet paper and hand sanitizer. Near the river on both sides are 2 fancy, double decker manèges with music. On the way to and from Trocadero is another playground tucked away with a fort. All of these are located on the western side. The playgrounds which come with age ranges written on them were the best antidote to "I'm tired." That and crèpes. Nutella and banana crèpes, if at DefCon 3.
