My island is only reached by ferry. The state ferries page to see the schedule for a single run is about 1/2 megabyte. I coded a 2k web page which lets you see any run you choose with a tap of the finger (or mouse, but usually it's mobile browsers I see using it).

https://vsta.org/ferry.html

https://www.wsdot.wa.gov/ferries/Schedule/ScheduleDetail.aspx?departingterm=9&arrivingterm=22&roundtrip=true