An option for reaching the high forest in and around San Sebastián is to go via El Pital, a community ecotourism project 9km (35 minutes by 4WD) east of Puerto López. Guides (if booked with plenty of notice) can take you on a 3-4 hour trek or horseback ride along trails that crisscross several streams. Trips include a local lunch.
Miguel at Hostal Yemayá in Puerto López can arrange tours including transfers, as the village is extremely difficult to find and best accessed by 4WD.