She had been out with Raffaele from lunchtime, then shopping in the late afternoon and round to his smoking a lot of dope from late afternoon. I think she left shortly after 8pm to go back to the cottage to change out of her day clothes and into something for her job handing out fliers to entice people into a bar and probably also to get some stuff together for her trip to Gubbio the next day.
Answering some other stuff: we know that she's in the vicinity of Piazza Grimana at the same time Rudy Guede is there because of the cell tower data (even though it's incorrectly referenced in part in Massei, the evidence was admitted in court). (The 40 minute pause in Amelie is corroborative of her time out of Raffaele's flat). She receives Patrick's message at 20.18 but doesn't reply until 20.35. My theory is she is talking to Rudy in the intervening minutes trying to get him to help her score. He doesn't have anything on him but says he can try and help and they arrange to meet up again in an hours time at 9.30. She wanders back to Raffaele's to give him the good news, texting Patrick back, turning her phone off and being at Raffaele's to answer the intercom at 20.40 to Popovic.
Some people don't like the idea of the drugs link but we know they all use and I think it is impossible to turn down the corroborated fact that both Amanda and Rudy are out and about at the same time in this tiny area around 20.30 and for that not to be linked to them hooking up again for a reason later. Their original meeting is random. They definitely met up again later. Why? I don't believe Amanda spontaneously planned a haze on seeing Rudy around 20.20. I believe the meet up and asking Rudy for help scoring is simply way more plausible.
She and Raffaele left his flat around 21.25 to do the five minute walk to Grimana to meet Rudy as arranged. If the starting of the torrent download at around 20.24 is proven, then for me that is absolutely consistent with going out. Torrenting uses up all bandwidth unless you've specifically set it not to and it is a very common practice for torrenting to be done when a user is going out or when going to bed. Kicking off a torrent as you go out is absolutely consistent.
I then say that Rudy had managed to score, presumably a little further afield than Grimana, either at the bottom of Garibaldi or in the Cathedral area at the top of Rossi. I have personally seen dealers in both and been offered drugs at the bottom of Garibaldi in broad daylight. The three then went to the cottage to take whatever they had and had a party in the kitchen per the story of Marie Pace.
I personally believe that Meredith had told Amanda at lunchtime that she had taken the cash out to pay the rent and had asked Amanda for hers, which she did not have. When Amanda met Rudy in the square the first time at around 20.20, I believe that Amanda went to the cottage and "borrowed" Meredith's cash to give to Rudy to help them all score. I personally believe that Rudy's story of Meredith being upset at the cash going missing and calling her a "whore of a doper", while yes a weak alibi for Rudy on the missing cash, is probably true. It may be that the call to Abbey bank at 22.00 was in fact Meredith's half-thinking reaction to finding the money gone since she's holding the phone at the time having just called her voicemail. It's the sort of thing we might all do for a few seconds before of course terminating it because she thinks "what am I doing? That's not the point - someone has taken the physical cash - who?". She then goes out to ask Amanda if she knows anything about it.
By this point the other three were off their faces on drugs and probably alcohol (remembering Raffaele and Amanda had now been taking drugs since late afternoon on their own admission) and were some 4+ hours into their bender. Amanda's reaction in that kind of state was probably to laugh at Meredith. This provoked the comment from Meredith and gives Amanda reason to explode at Meredith whom she knows disapproves of her messiness and the types of people she mixes with (said by Meredith to Sophie Purton). Amanda reacts badly and escalates it into a fight and the assault as the other two joined in. The assault escalated to a point where they felt they "had" to kill Meredith because otherwise she was going to tell the police. It was probably a unilateral decision by Amanda in my opinion as she realised this is where they'd got to.
Rudy leaves the cottage, running straight from the bedroom to the front door as shown by the footprints. Amanda and Raffaele are there long enough for Raffaele to wash off blood in the shower or in the bidet, leaving his footprint on the bathmat and Amanda to wash in the sink at the same time and they have a hurried clean-up in general, although Amanda will come back the next morning. When they leave from the drive, snaking up into the carpark and running along the metal stairs and then round into via Melo, multiple running footfalls on gravel, on the metal steps and on the pavement are heard by multiple witnesses around 23.30. FOA don't like anyone to remind them that it was not only Ms Capezzalli who heard the running on the driveway from a flat that is absolutely directly opposite the gravel driveway but also by Maria Dramis who was in a bedroom on the *other* side of that appartment block and who heard them running along via del Melo, having cut through on the metal steps and then run along to the steps running down the side of the basketball court. Via Melo, which is completely pedestrian and really in effect a back alley brings you out half-way down the steps directly behind one of the basketball hoops and about 15 yards from the vantage point at the edge of the court where you can observe down onto the gates which is in itself 15 yards from Curatolo's bench.
Here's the exit route. Plotting of the witnesses is approximate. The reason that they went like this is because the area in the yellow box is a busy intersection and they could easily be caught in headlights as the three roads intersect. Instead they sprinted across the road from the cottage gate to the ramp up to the carpark and then up the metal steps before cutting into Via Del Melo which is little more than a back alley.