Not even sure where to start?!?

Your best bet is to spend some time moving around the country and trying different places out. The country may seem small, but it is challenging getting from place to place. By seeing all that is available, you will have a better understanding of what you want and where you would like to live. And maybe, CR is not for you. It's not easy living here and it’s not that cheap either. You really have to have a good mind-set if you want to handle what this country can throw at you.
My biggest advice for you: don't take anything for granted. People come down here with preconceived notions and get terribly burned. You are an immigrant and it is good to keep that in mind. There are hundreds of sites that can offer you tips and suggestions. Take them all with a grain of salt.
If you want to stay longer than your 90 day visa, travel to Panama or Nicaragua and see what they have to offer. It’s good to have comparisons.
October/November is the end of the rainy season on the Pacific side. By December/January it gets dry and hot. The Central Valley is cooler, wetter, and very windy that time of year. The Caribbean is hit or miss. Late Atlantic storms could kick up nasty weather, or it could be blissfully beautiful.
Start learning Spanish now.
Good Luck!