I think if travel to camp was limited to only being accessible from a waypoint, you could have scenarios like falling into the Underdark where you literally can’t long rest until you find a waypoint down there, which I think would work well. And if you’re in really bad shape when you’re down there, you would need to rely on mechanics like stealth to try and avoid combat in order to find the waypoint, which adds an interesting dynamic. Sure that wouldn’t affect the first part of the game much, but hopefully as the game progresses, there would be more instances where you can’t just backtrack to camp.
Agreed. The Underdark should be a scary, stressful place to explore. Especially if you're unprepared. Having to find a waypoint or a dedicated camp site or have very limited rations would all improve the atmosphere imo.