I'm a 47 yr old female traveling alone in CR for 10 days early May 2016.
I am torn between the Carib side vs Pacific. Definate wants:
Rafting on the Pacuare River, 1 or 2 days?
Ziplining.
Hanging out on a nice beach where it is safe.
Hiking, Enjoying national park, best bang for seeing wildlife.
I love adventure, not too extreme, traveled in exotic places, Africa, tailand, NZ, Aust., Most of Europe, so can be on local bus. Also, accomodation, $20.00 separate room, share bathroom is fine.
Would someone be able to put the recommendation together?
I really am excited! Meeting others would be cool too, maybe share travel. MAY 7

I would head for Cahuita and surroundings on the Caribbean coast. I don't know about zip lining but it's got the parks, the wildlife and the beaches. It's a 4 hour bus ride from San Jose. Spend your first and last nights in Alajuela near the airport.
Costa Rica can be many things to many people, and for all levels of travel style, but, there are differences between the caribe and pacific. For your budget, the caribe side will be far easier to achieve than on the caribe side. Also, using public transport, is much easier, and actually the best way to get about on the caribe side, versus the Pacific and Central areas, as time will be your enemy getting about logistically.
10 days is a perfect amount of time to enjoy a lot of nature, rich bio diversity, and wonderful beaches, as well as raft the Rio Pacuare, all on the caribe. The caribe side is more authentic, for lack of a better description, than the more developed and tourist popular Pacific side, though the main thrust of popularity on pacific side is cool surf towns and nice beaches.
The caribe side possesses some of the best beaches in the country IMO, with Playa Cahuita NP, Pt Viejo area, and beaches south Cochles, Chequita, Punta Uva and Manzanillo Ganduca. All reachable on a rented bike, bus, or taxi hire.
It also has a more laid back afro caribe feel, far slower pace and little development, its a tad more dicey for some, more a euro backpacker feel, with travelers coming and going from South America, via Bocas del Toro Panama. It does have a more party element, and drug issues, as its cheap and plentiful, and the coast is also more rasta, and also has more poverty around Limon. Its not for the All Inclusive types or people that want to engaged with the locals, more resort types would maybe feel intimidated I suppose. But its gorgeous, has a great cuisine/foodie scene, and a nice mic of locals Ticos, Afro caribe, and Argentinians. So a tad bohemian more than anything.
Tortuguero Rainforest and canals is a must. Rafting the Rio Pacuare is a must, do this from caribe side, and get dropped back in SJ at end. 1 day is fine.
Cahuita is a funky jive afro rasta town with great music and a fantastic park to hike full of monkeys and sloths and birds and great beaches.
Zip Lines I am not fan of, sort of touristy, I prefer to have a local guide and learn about the eco systems, lifestyle of locals and nature, and its much cheaper and has a richer reward, learning, and supporting a local. You can't learn or enjoy anything in the a natural setting, from a steel cable above the forest floor...scaring wildlife off in all directions.
I like the Caribbean as well: lots of wildlife, beautiful beaches (wild natural beaches bordered by jungle)and fun hiking. You can get to Tortuguero by bus/boat from San Jose, then to Cahuita by boat/bus and to Puerto Viejo and the beaches south of PV by bus. The National Park in Cahuita is amazing. We went without a guide and saw lots of wildlife. South of PV we liked Punta Uva and Manzanillo. Manzanillo is a small village with a wildlife refuge (Gandoca Manzanillo). Hiking for a little bit there on your own is fine but if you go far it is better to go with a guide. Ziplining is possible near PV (check under activities on the puertoviejosatellite link provided above). You can find cheap rooms in Cahuita (our hotel was $20 for a double with private bathroom). We did not stay in Puerto Viejo but I heard good things about Pagalu ($28 for a room, dorm is cheaper). In Manzanillo prices were higher but we discovered Cabinas Heliconia. We liked it there ($30 for a double, not sure if they have single rooms). Cabinas Bucus was $35 for one person.

Agree that the Caribe side fit's your list.
Start out in Tortuguero, 2-3 nights, then head south to Cahuita, cool small town and great NP, easy hiking and tons of wildlife.
The beaches south from Puerto Viejo to Manzanillo are the best but there pretty nice in the Cahuita area as well.
1 day of rafting the Pacuare River is fine, outstanding and fun float. Do it on your last day of traveling, they will drop you off back in San Jose or Alajuela. Alajuela is a nice small town 10mins. from the airport.
You might want a guide for a day if you go to Tortuguero, the rest is easy on your own.

Hi, thanks for the info. Yes, I have been leaning toward the Caribe for all the Nature, rafting, canoeing, BriBri, etc. My questions is, between May 7-17 is it still busy enough that I can relax on the beach and not worry about "being alone". I do enjoy meeting up with people, but remember I am a bit "older". Is there an older crowd too? Which places do you recommend me stay for a reasonable price $20-$30 share bathroom or not.

Hi, thanks for the info. 2-3 days in Tortuguero? If I'm taking a boat into the village, is the canoeing/kayaking the same experience? Which accommodation do you suggest? Also, what else is there to do, I'll be there May 8th, 2016. So excited? Will there be a lot of rain at this time? Mosquitoes, what else should I be interested in? From Tort, I will take the boat down to Moin, then taxi Limon then public transit to PV...right? Do you know the cost of this transportation?
Taking a canoe or kayak will allow you to explore in the small canals and rivers where a boat can't go, and also be quiet to get up near wildlife.
For prices, read the links. Its cheap.
Mozzies are a issue all over CR and the tropics. Dengue can be an issue in rainy season, ask the locals/bartenders and guides about outbreaks, as well as Zika issue. Is what it is.

**what about currency. I'M Canadian. To change to U.S is mucho exchange. Should I exchange to colons for buses, local food, accomodaton, park entrances?
If you can somehow get US dollars, maybe $500, before you leave at a good exchange rate; that would be good for backup and emergencies. Otherwise I would rely on ATMs like most people do. Of course it helps if your bank card has some low fees on transactions but expect to pay at least some fees every time you use it. Therefore, it is better to take out all that you need for a length of time rather than keep going back every day. There is a bank with an ATM right in Cahuita. Yes, For local stuff use local currency or even with US dollars you will lose a little bit each time which adds up. I would pretty much forget about Canadian dollars entirely. In Cahuita there are some cabins a ten minute walk from town in Playa Negra for about $30US and you should have no trouble finding a nice room either right in town or elsewhere. Age wise, I think that you would feel more comfortable staying in Cahuita than in Puerto Viejo which has a younger crowd. There are several local buses that leave from and return to the Cahuita bus station (near the bank) every day. They will take you all the way down to Manzanilla were the coastline is spectacular and back all in a nice day trip. I recommend renting a bicycle in Puerto Viejo and riding down to Manzanillo at your own pace.