Foreigners/Gringos traveling to and from Costa Rica, have to go through Rivas, so it is not like you will be the token, as this small town has been seeing gringos for decades. Some do call it a night there after the border or before the border for a early morning crossing. Its main purpose for a traveler would be the access to a ATM for Cordobas. The other is you can get on/off the Tica bus here that goes between the Capitals of Managua and San Jose CR.
It is also the provincial head of ministries, courts, police and public services.
The most alarming fame it received was in a case where a Gringo was dating a local Nica and she was murdered, and he got pinned with the crime, but it was a hocus pocus prosecution and a kangaroo court/trail. The emotions of locals flared to a hostility, due to their resentment of gringos and land grabs and development all around SJDS and the Pacific coast. he was a scapegoat of sorts, and had a wild ride in a notorious prison for year until it was all sorted out.
https://en.wikipedia.org/wiki/Eric_Volz
And then there was this poor chap that may have had his hands in drugs on some level, but it was ugly. It also didn't help that he was perceived as Afro. There is a racism in these parts, and even amongst the people of each country towards each other, Costa Ricans (Ticos) always point fingers at Nicaraguans (Nicas) as thieves and no good bums. Both countries peoples hold contempt for afros that are mainly on the caribe coast, or in the case of Nicas, Miskitos.
http://www.huffingtonpost.com/2012/09/18/jason-puracal-freed_n_1893827.html
Other than that, Nicaragua for the average Joe is just fine, and the people of this country are salt of the earth, hard working and honest, and very sweet IMO.
To be fair, I can count how many Expats/Gringos have been murdered in Costa Rica...but it aint pretty either.
Get the MOON Nicaragua guidebook if you are considering a move to Nicaragua, it gives a great introduction and history lesson of what the Nica have been through, what makes them tick, and why the country is at the point it is today, the people have been thru hell, no help and thanks to foreign policy and covert operations from the US Military and CIA.
What surf school/Camp/tour? I have been surfing in CR for 15 years...
Adventure Travel to Colombia, Costa Rica, Nicaragua, Honduras, Guatemala, Mexico, Thailand, Burma, Laos, Cambodia, Vietnam, China, South Africa, Morocco, Turkey, EU, USA National Parks, enjoying culture, cuisine, motorcycling, scuba diving, surfing, sailing, rafting, hiking, fishing, camping, nature, wildlife. Get a Guidebook, and get lost!