Nicaragua - Costa Rica - Panama

My friend and I are leaving in a couple weeks for Central America. We are flying into Managua, Nicaragua and making our way to Panama City and are flying from there to Columbia. We have a month in Central America between the three countries. We would love suggestions on things we must do and see and how much time you would recommend spending in each country. We are both very adventurous and athletic. We are up for anything and love trying new things. We aren't into super touristy things and would like to avoid those things as much as possible. Both recent grads, we are also looking for inexpensive things to do and places to stay.

Any tips you have would be greatly appreciated. Thank you!

Nicaragua:I think you can get to the corn islands cheaply, if you take the bus & ferry. I'm fond of Casa Blanca, on Big Corn.
Costa Rica: I found puerto viejo talamanca tolerable, playa tamagringo the opposite. were i to revisit, i'd check out montezuma.
Panama: when youre done with talamanca, keep going to the sixaola crossing and continue to Bocas town. Hang out at Hotel las Brisas. In Panama city, you got to stop in at Mamallena Hostel. for about $200 a head, you can go sailing in Kuna Yala (www.theandiamo.com)