In addition to wilderness survival and travel, there are several house rules in play that you should familiarize yourself with:
This variant (variant) changes the times of short and long rest.
Short Rest
The first short rest of the day is 1 hour, the second short rest of the same day is 4 hours. A character can spend one or more Hit Dice (HD) at the end of a short rest, up to the character's maximum number of Hit Dice (level). Spellcasters can prepare spells during a four-hour short rest but will not regain spell slots.
Long Rest
A long rest is 3 days during which a character sleeps for at least 18 hours hours and performs no more than 6 hours of light activity, such as reading, talking, eating, or standing watch.
Players choose to spend their HD to heal ability loss, drain, or damage separately as follows:
One Hit Die to recover one point of ability score loss.
One Hit Die roll to recover spell/other drain.
One Hit Die roll to heal damage.
A short rest is needed to dispel exhaustion levels 1-3, long rest to dispel levels 4 or 5. Recovering from exhaustion does not consume hit dice.
*Recovering Spent HD
Hit Dice are recovered by rolling a DC 13 Constitution check for each spent HD at the end of a long rest, before any healing. Disadvantage may be imposed under harsh conditions, with inadequate shelter, or if unable to rest. Likewise advantage may be granted under good recovery conditions and medical care, such as at a sanctuary or house of healing.
Recovery during long rest assumes you have access to good shelter, food, sleep, and care. For each one of these conditions not met, the type of Hit Die rolled for recovery is reduced by one. This means 1d12 becomes 1d10, 1d10 a 1d8, and so forth down to a minimum of 1 point. See Chapter 5 in the DMG for more on conditions and survival.
Shelter: This assumes a restful and clean environment such as a private inn room or residence. In the wilderness, this requires a DC 13 Wisdom (Survival) check with adequate tent and winter bed roll (substitute campfire for either). A single character may make this roll for a group.
Good Food: A hot meal or good quality food is needed for healing. Characters can use the Foraging Rules from Chapter 5 of the DMG if you need to find food in the wilderness. Finding quality food with foraging is difficult. Roll twice when foraging and if both rolls are successful, the food is of high enough quality to satisfy this requirement. Otherwise it is simply enough to keep you from starving.
Sleep: Sleep or meditation is required as normal for your race. Without adequate shelter or if interrupted with combat this may require an individual DC 13 Constitution (Survival) check to satisfy this requirement. This roll may be modified or made at disadvantage under harsh conditions.
Medical Care: Having proper care is important for a speedy recovery. Characters proficient in the Medicine skill may make a DC 13 Wisdom (Medicine) check to provide proper medical care to themselves or others. The DC is increased by 2 for every patient over the first and is made at disadvantage without proper medical supplies.
Starvation and Water
As mentioned in the Good Food topic above, food is essential for survival and healing. Additionally, characters may suffer exhaustion from starvation or dehydration. The rules covering Food and Water in Chapter 8 of the PHB, and Foraging rules from Chapter 5 of the DMG, should cover this well.
Characters might sustain a lingering injury under the following circumstances:
When it takes a critical hit
When it drops to 0 hit points but isn’t killed outright
When it fails a death saving throw by 5 or more