The short answer
Lava Hot Springs is not a resort where the lodge, pools, restaurant, and room all belong to the same property. The state-managed hot pools sit inside a small town, and the lodging choice is mostly about walkability, family logistics, and whether you are staying one night or building a full Idaho weekend around the stop.
For most visitors, the best lodging is close enough to walk to the hot pools. That keeps the nighttime soak simple and makes the separate Olympic Swimming Complex easier to use as a daytime family activity. Choose cabins or RV stays only when space, privacy, or a longer trip matters more than a short walk.