From Quito the journey is possible but too long, so maybe you should break it in two. Or fly from Quito to Guayaquil and then take a bus to Montañita.
Airconditioned buses from Guayaquil leave 3 times a day, at 5.00 - 13.00 - 16.30. The journey takes about 3 and a half hours.
Don't forget to take a sweater or a jacket out of your bag before you get on the bus or..you'll freeze to death...
About walking around the village your well trained feet are enough but you can also rent a bike.
If you need transportation from Guayaquil to Montanita, Eric will pick you up from the airport or your hotel. You can pre arrange a pickup, and he will be there on time(and probably early). He has a comfortable van for the 3-4 hour trip. He does this service for some of Montanita's hotels, so you are in good hands.
Since we were a big group we decided to rent a van to go to the beaches. This was great because we went to Montanita and then went to Salinas and then to Guayaquil. We enjoyed the coast at our own pace with out being on a schedule. The worked great for us because we were with locals that knew the area so we didnt worry about getting lost. Althougth even if you dont know the area very well i doubt you would get lost because there is one road each way.
The van wasnt big enough for all of us so some of us went in another car. When we got to Montanita another two carloads of people joined us. It was great.
I forgot to ask my cousin how much it was to rent the van. I know that in Quito car rental was expensive and you get a cheap piece of crap car. I cant even imagine how much it is for the van. I need to ask him so I can give him my share. :)
Montanita is so small that you don't need any transportation means to walk around. Even to discover some desert beaches on the area, you just need to walk along the beach in front of you.
Buses run the Routa del Sol (the coastal road) regularly, and can be flagged down from anywhere. The cost is about $1 per hour of your ride.