Santa Elena is small enough to walk across in fifteen minutes, but the cloud forest reserves and the canopy parks are spread across the surrounding ridges and you will need transport to reach them. Public buses run several times a day from the village to the Monteverde Reserve and to Santa Elena Reserve; the schedule is posted at the bus stop on the main square.
Many travellers take taxis or pre-arranged shuttles from their hotels. Most tour operators include hotel pickup. Renting a 4WD is convenient if you want to do a couple of reserves a day plus the more out-of-the-way places (Curi Cancha, Sky Adventures, the cheese factory). Cycling is theoretically possible but the steep gravel roads make it harder than it looks.