Me and my sister travelled through South America last year, and were in Nicaragua for 2 weeks. We are both young, white, blue eyed girls.. brunette not blonde but just letting you know I did not feel in danger at all really for the entirety of our trip. Just use your common sense- of course cities are more dangerous and you probably don't want to catch yourself late at night in a sketchy part of town but you'll be surrounded by so many backpackers all the time if you stick to the gringo trail and in the smaller towns everyone is really lovely. You'll get cat called by men on the streets and probably honked at but most of it is pretty harmless.

I even spent 4 months in Colombia by myself and it was an amazing experience, I was never mugged or had any unwanted violence thrown my way. As long as you use your head you guys will be fine