Rimworld Guides and Walkthroughs
For the most part this page is going to be talking about the Hospitality mod since without this mod guests will not act the same way in your colony. With the Hospitality mod guests will occasionally show up to your colony from factions you have a Neutral or better reputation with and they'll stay a few days. During this time you can 'Entertain' the guests if your colonists have high enough Social skill and build better relationships with the guest and the faction they originate from.
Once you download Hospitality you'll get another column under your 'Work' tab which allows you to enable/disable entertaining guests for your characters. You will also get another tab at the bottom of the screen titled 'Guests' which allows you to see all of the visitors at your colony and provides you with information about them (pictured below).
Guests can be recruited to your colony once they become friends with enough of your colonists, as you can see in my screenshot below I could recurit Archer if I wanted to. Recruiting a guest will damage your reputation with whatever faction you recruit them from but usually that's not too big of a deal since reputation is easy to increase.
You can also set up your own shopping area for guests and allow them to purchase new clothes or materials that you have excess of. I recommend you be careful with this though as they will purchase things you need and don't want to sell unless you set up the proper shopping areas. You can also sell the guests food when they come - sometimes they bring their own but other times they expect to buy some from you when they visit.
I strongly recommend against letting the guests take your food for free because they will drain you dry. They'll eat every meal for free and before they leave they'll stock up on 3 - 5 meals each. You'll get good reputation increases with their faction if you let them eat for free but you won't be able to upkeep the food costs of your colony and them for more than 1 year.
As for the upsides of taking care of your guests and using this mod, a healthy and happy guest will help you around the colony with work. Guests are also the best source of income in the game if you ask me. If you allow them to purchase food and clothing from your colony they'll spend hundreds of silver each time they show up.
Guests who are happy with your level of hospitality will also give you gifts when they leave. Sometimes what they give you is total junk like clothing or a weapon but other times they'll leave you goodies like Glitterworld Medicine, Components, Plasteel or even Advanced Components. I personally am a fan of this mod and the guest system they use for it - it adds a bit more depth to the game and it gives the 'Visitors' an actual purpose when they come to your colony.
To keep your guests happy the most important thing you need is beds built for them. When you select a bed you'll have the option of making it a 'Guest bed' which will make the bed sheets purple. You can actually charge guests silver to stay in these beds too if you'd like. I like to make a residential district for just guests somewhere in my base along with a shopping center nearby for them to shop at.
An alternative which I often do too is I allow guests to shop at every warehouse in my base except one. Then I store all the items I absolutely do not want them to buy in the one warehouse they can't shop in. If you're playing on a higher difficulty in Rimworld you may not be able to afford the time/cost of building each guest their own room in which case you should settle for barracks.
<Guest Rooms>
<Guest Barracks>