When choosing the starting point on the map, there are a few things to consider with the lost tribe. In this scenario, almost no research is unlocked, and the speed of research is much slower.
With this handicap it will take some time to get electricity. Until then you have to heat your base in another way and cool your food storage. Therefore, wood is the most important resource to start with. So use your wood supply sparingly, otherwise you will freeze to death in winter.
The First Few Days
You should use the first days of the new colony to build dignified housing for your colonists. You should definitely plan in advance where rooms are to be built later. This way, you don't have to make major changes to the layout of your base afterwards.
Summer is there to gather enough food for winter and to build a shelter for your colonists. Keep in mind that raw food such as rice or corn will last longer than cooked meals - these only last for a few days. So only cook as many meals as your colonists need for the next few days.
You can store all things in the refrigerator that would spoil without refrigeration. This of course includes hunted animals, meat and other foods. At the moment you don't have any electrical cooling for these items. To protect food from summer heat waves, the wall of the refrigerator should be 2 blocks thick. This insulates the wall better.
In your base itself you have to heat the rooms with campfires, otherwise your colonists will freeze, especially at night. Also put torch lamps wherever possible, because they don't like to be in the dark. Torches also help somewhat in heating the room, but not as much as a campfire.
Later you can improve the cooling in your food storage with a Passive Cooler. This will not freeze your food, but it will keep it fresh longer than without refrigeration. The Vent to the outside is currently closed, in winter you can open it to freeze the storage.
Another advantage of a mountain base is that you are not directly exposed to the outside temperature. Even during a heat wave, the base remains at a moderate temperature.
Due to the planned layout of the base, the workshop can be easily expanded and additional rooms can be added. By researching complex furniture, the Bedrolls can be replaced with real beds. Also, additional furniture can increase the comfort for the colonists considerably. Keeping the colonists in a good mood will prevent breakdowns and vandalism.
Beer for a Good Mood
You can also use the "Beer brewing" research to build a small beer cellar. All you have to do is grow hop plants in a field, which will later be mixed into wort in the brewery.
The wort is then put into a fermenting barrel, where it becomes bottled beer after a few days. If your colonists drink beer, they will receive a mood buff (+10) for a while. So beer is a great way in RimWorld to boost your colonists' mood.
As your colony continues to grow, it is time for a larger recreation room. Having an impressive rec room will also boost the mood of your colonists!
Especially in a mountain base, you can improve the rooms without using a lot of resources by smoothing the surfaces of walls and floors. If you keep the base clean at the same time, your tribe will feel very comfortable.
A major turning point in the lost tribe is the completion of the electricity research. First you can dismantle all the torches and replace them with standing lamps. This results in needing a lot less wood in the future.
Next you can electrify the heating and cooling. To get started, you can do it as shown in the screenshot, with a mix of generators and a wind turbine, including a battery.
Electricity makes things a lot easier, but new problems can also arise. From now on you will encounter the Zzztt-event more often:
Electricity Generation through Boomalopes
In mid-game, your base could look something like this. Boomalopes roaming the map enabled me to switch all of my electricity to fuel generators. If you manage to tame boomalopes, they'll drop fuel on a regular basis. So boomalopes are one way to power your base.
To keep fuel supplies high, you can supplement fuel production with a biofuel refinery. Here you can use meat or vegetarian products to produce fuel.
Tip: Use the raiders bodies to produce fuel.
In the end-game you can build a protective wall in front of your entrance. Leave a small gap open as in the screenshot above, there the raiders will then run through. In this case, they also get a debuff because they have to walk through the wet.
All high-tech devices are placed under the workshop, such as the Comms console for orbital trading and pod launchers for transport pods. This allows colonists to be quickly sent on expeditions to gather resources in other regions.