Ancient mystery authors rejoice! Stanford University has produced an online trip planner: one for getting you around the ancient Roman Empire. It comes complete with route planning, schedule estimates and fare costs.
My only complaint is all the fares are calculated in denarii rather than drachmae. But then, the hyper-inflation of the post-Alexander period throws out the costs for me anyway.
I heard about this from the excellent Ruth Downie, who writes the equally excellent Ruso mysteries starring a medical doctor in Roman Britain.
I instantly tested the system on a route for which I knew the answer. Those of you who've read The Ionia Sanction will recognize this map:
This is the route Nico and Asia took from Athens to Ephesus, aboard Salaminia, the fastest trireme ever built.
Like any ancient author dealing with travel, I worked it out with a map, a ruler, and by knowing
I figured that Salaminia could do it with only a single overnight stop and two very long days. Orbis produced 2.4 days for a standard boat on its quickest route, or 4.5 days if I restricted it to coastal waters and only daylight travel, which would be your average trader. I did notice you have to be careful with the options. If I left road travel turned on, the boat stopped on one side of an island, people got off, crossed the island by horse or donkey, then got back on another boat. Which is obviously unrealistic, but since I did allow it in my choices it's fair enough.
With a little common sense, and by modifying the result with any specific knowledge, it's guaranteed to save you piles of time. I think this thing is just awesome. This is what historical research should be in the modern world.