Well, if that works for you & your group.... But from the outside this seems a bit absurd.
Question: Does this influence the types of adventures or classes your players choose? After all, if I were playing in a game where the DM was screwing with long rest recovery like this I wouldn't pick something like a wizard to play.
Why? Surely not for verisimilitude. There is no logical reason you can't get a good rest in the wilderness if you know how to take care of yourself and your fellow travelers. I can see requiring the party to make their own safe, temporary "settlement." If they took a beating, they may need a bit more comfort and care than a tent, but why not let them use their survival skills to find and create a safe place to recuperate.
I only allow Long Rests in safe settlements for balance reasons, not for verisimilitude. Let's take an example: the classic module X4 Master of the Desert Nomads. Although it could be a whole bunch of other modules; most of the Dragonlance saga, many Mystara or Dark Sun modules, really anything with a hex-based map. The combat encounters are miles and miles apart.
Let's say the average overland journey is 100 miles. It certainly is in my campaign world, with 36 mile hexes. That's four days of travel. Now, the DMG clearly outlines the expectations around number of encounters per day. This means that I have three choices as a DM for handling overland travel:
1) Nothing happens, and I just hand-wave the journey. Encounters only occur in set-piece locations (dungeons, caves, etc) where I can "force" a certain number of encounters per day. But that limits my ability to tell a story. Lots of classic fantasy tales feature "events on the road". Unacceptable.
2) Sufficient encounters occur over those four days so that the balance guidelines are met. That means 16-20 combat encounters just to travel 100 miles between Town XX and Ruined Keep YY. That's incredibly boring. It'll take my group four sessions (four weeks, real-time) just to get to the Ruined Keep. Also, it ruins the story just as much as having no encounters; the journey to the Ruined Keep took four times as long, and was four times as dangerous, as the Ruined Keep itself.
3) They have just 1-4 encounters over the journey; enough to keep it interesting and tell a story for being on a dangerous and unknown road, but not enough to draw out the trip to ridiculous lengths. But here we have a challenge. Either every single one of those events occurs in a single day (unlikely in a four-day trip, and incredibly unlikely in a 10-day or 20-day trip), or they're only going to face maybe one encounter per day. Most wilderness modules explicitly state that there is a percentage chance of
one encounter per day. Many wilderness modules even go so far as to define events that occur on certain days (Day 32: Draconians Attack! Day 41: Snow Storm!).
Contrary to ccs's quote,
Option #3 is what causes problems with character choice. If you know (or can reasonably expect) that you will be Long Resting after nearly every wilderness combat, there is no incentive to conserve resources at all - and it screws with party balance. The wizards and clerics burn off every single spell, massively overwhelming the short-rest types (monks, fighters, etc). Further, wilderness encounters nearly always have to be "Deadly" (as defined by the DMG) to provide any kind of challenge. Even if you shake things up and surprise the party with two encounters in a single day, they both have to be pretty damn hard to challenge the average party. And that, again, harms the story. If every fight in the wilderness is potentially lethal, how do regular folks even survive out there?
My approach (Long Rest only in safe towns) effectively forces the same type of balance as a typical dungeon-based adventure. The party has no idea what they could encounter. It could be a single Deadly encounter, or several Medium-Hard encounters, or a bunch of Easy encounters. The full casters will need to conserve some spells, because they have no idea if they will hit other fights on the road before they reach Waterdeep (just like if they were exploring a dungeon of unknown size). I can increase or decrease the difficulty of the adventure simply by adding or removing encounters, because the party can't simply reset after each fight by camping. And I achieve a level of
world realism; several fights with wolves are a legitimate threat, because they will drain party resources over a week of travel - as opposed to every wilderness fight being with a ton of werewolves, because I know that the wizard and the cleric will be dropping every spell slot (and then the party will simply break out the tents, and restore to max).
It works for my group, at any rate. It adds a sense of danger to the wilderness. That 200-mile stretch of desert becomes a real challenge, because the PCs won't be regaining any hit dice or spell-slots until they get to the oasis on the other side; no matter how many days it takes them. There's now a reason for avoiding unnecessary combats, conserving spells, and using caution.