Once you get to your accomodation, you're going to need to find a way to get around aside from hoofing it. Whatever minivan-bus service is going isn't going to meet your needs.
Bicycle rental is a possibility, but there are some huge hills around Lastovo village. Biking around Pasadur looked pleasant.
Scooter rental is better, these are available in Lastovo village at the tourist office or at a cafe. Better scooters are available from a family in Zaklopatica Bay. Cost is 60 kuna/10 euros per hour.
Scooters and bikes should be available in Ubli and Pasadur.
Check with the tourist office for more information http://www.lastovo-tz.net/
Ferries and catamarans to Lastovo depart from Vela Luka, Korcula (an hour bus ride from Korcula town) and arrive at Ubli. Check schedules at www.jadrolinija.hr.
Not much to see in Ubli, you'll soon move on to another place. Arrange for your host or hotel to pick you up (especially if you arrive in the evening). Otherwise, sometimes there are minibuses that greet the ferry and go to Lastovo Village.
There is a jadrolinija office, tourist office (of varying opening times), and a cafe at the ferry port.