You need to look at a map -- here is a giant one -- http://www.orangesmile.com/destinations/img/athens-map-big.jpg -- click & it gets huge... use side-slides to navigate & put Acropolis at the center.
You DO understand do y ou not, that the 6-part Landmark Sites ticket includes Dionysus & Odeon theatres... you pass them when exiting the Acropolis site to the SOUTH. THe Acropolis Museum is right across the pedestrian promenade from that exit. Aeropagus Hill (Mars Hill) is just at the entry to Ancient Agora ... it's #11 on this map. You can also see the relative distances to the PNyx at #18 (spelt Pnika here). You can also see the relative position of the National Garden here... the Panathenic Stadium is just off the map to the right, beyond the part of National Garden that has the Zappion (which is a monumental building totally empty). Stadium costs about €5 to enter, you can look at it thru the fence. You also can visit HADRIAN'S arch -- right out in public on Amalias Avenue, and Temple of Zeus, next to it.
It's hard to advise you when you don't tell us WHEN you'll be in Athens (you may have shared this on one of your other numerous messages, but we don't go back & research -- please recap briefly each time!). It makes a big difference if you're doing this on a hot August afternoon, or a cool September or May day.
Have you considered doing the very cheap and enjoyable HAPPY TRAIN? - http://www.athenshappytrain.com ?? Unlike the hop on/hop off BUSSES (which can only go on big streets), this cute choo-choo (a jeep in disguise with open cars) can go on pedestrian lanes, and tour you around all the major landmarks in Plaka area. Takes only 40 minutes, hop on/off another one comes along cost about €5-6. Website gives exact route... you take a look, decide if you want to hop off ...or just enjoy a drive-by.