Hi Pete,
Thanks for checking out our books! Glad they have been helpful. There are a couple of good options for an overnight in between Puerto Viejo de Talamanca and La Fortuna. One place we really loved was Casa Rio Blanco B&B near Guapiles and Braulio Carrillo National Park (great park for hiking- we saw an anteater there!). There’s not much else in the immediate area, but the B&B is a little ecolodge right on a picturesque river and is really all you need for a one night stay. Here’s a blog post we wrote with more info about the park and the hotel: https://www.twoweeksincostarica.com/braulio-carrillo-national-park/

Another option is Puerto Viejo de Sarapiqui, like you suggested. This is a great spot for birding if you’re into that and also just a good place to experience authentic Costa Rica. There are a bunch of ecolodges in that area, but we’ve stayed at Tirimbina and really liked it. They have a huge hanging bridge on site and some trails so it makes a good base. Here’s a blog post with more info: https://www.twoweeksincostarica.com/tirimbina-an-eco-treat-sarapiqui/