I live in Oulu and we have two courses that you can reach by bus. One will require some walking and with other three car is the only option. Locals are friendly and happy to give you a ride if you ask around in Facebook. If you decide to come here I would love to be your guide. So yeah, it is very much possible to play without driving, but you will need some planning. Most small cities don't have public transport, so your best bets would be Helsinki (and smaller cities around it such as Lahti, Vihti, Espoo and Vantaa), Turku, Tampere, Jyväskylä and Oulu. There are many smaller cities that have courses near railway stations so you could easily walk.