You are in the tropics, so of course there are snakes and insects. However, in my many trips to Costa Rica since 1994, I've never seen a wild dangerous snake except on a guided hike when we were looking for them. Even on my
reforestation farm, where we wear the usual rubber boots when tromping around in tall grasses, I've never seen a snake. Of course, we go onto paths where there are locals to guide us and usually a dog or t
wo to scare away anything dangerous in the path ahead.
We generally have to go to Reptilandia (right up the road from Dominical) to see snakes. If you want to see some incredible snake activity, go to Reptilandia on Fridays during feeding time.
We've also experienced almost no mosquitoes during the dry season. We did run into mosquitoes during the rainy season when we were tromping around outside, so have learned to bring a good insect repellent along, and wear very light long pants and long-sleaved shirts if we don't want to bother with the bug spray. In some places, sand fleas can be an issue. And of course there are ants everywhere, so you must always be watching where you step.
One thing we love about the no-see-um netting and our big tent, is that it is a completely bug-free zone.