It's not hard to download SITA bus schedules, but make sure you are looking at the high-season schedule. It may be hard to find in the winter. In general, there is little public transportation in this area at night, so don't guess about your end-time for the day out. We spent a night (pre-scheduled) before several in Sorrento, in Naples because our flight from England arrived after dark. If you can't get to Sorrento at night, you certainly can't get around the AC at night! I would expect taxis to be expensive, even for a shorter trip. This is a high cost area, and there is only one two-lane road along the AC, which is slow going.
I have not done any of this outing except for visiting Ravello, which is quite easy from Amalfi. I think you will have less time to linger than you will want. You will encounter huge crowds, and should make a reservation for lunch. We ate at Flauto de Pan, at one of the hotels in Ravello. But you can expect crowds everywhere in June, and lines for some busses. But because the bus in Maiori terminates in Amalfi (check the bus schedule), it won't be like trying to get back to Sorrento from Positano on a bus. Do not plan on the last bus of the day unless you get reliable information that this is okay. And remember that southern Italy is not as well-organized and infrastructured as is northern Italy.
I found a blog that says the Path of the Lemons is 400 steps up and 400 steps down, and takes one to two hours. This should be easy to research online.
We didn't happen to see Lemon Tiramisu, but "Delizia al Limone" is a local specialty.
