For the person who's host is ready to take them in but not the spouse and child...am sorry for that situation. Its tough.
1) Rental Apartments: You need credit to officially rent any apartment...however, there are people who rent out their furnished basements/rooms for extra $$ here and there, and only ask for extra deposit.
2) Bank Accounts: You do not need credit history to open any bank account in the US. All you need is the minimum deposit that each bank requires...however; is there any reason in today's US bank status why one would want to open a bank account? I have not had a bank account for six years now because the Credit Unions are much better than Banks. They do not charge all those fees for this and that here and there till they milk you dry, and they really helped me build my credit when I came here...borrowed like $500 and deposited it in savings for them to pay using the same. Then borrowd $1000 etc and within no time, I was having better credit score than most people. Of course, it showed, that it was new...but the score was great.
3) SSN: 10-15 days in the East Coast as far as I know. (For those who are planning to have families when they come... it's even shorter for children. Once they are born, the hospital helps with application and a few days after you get home - the card arrived. I remember with my 3rd born he was born on a Friday AM, and on the next Tuesday - the card was in the mail!
4) Buying Cars/ car rental: There are a lot of dealerships that will sell you nice starter cars for about $1000 or even less. You can either be so blessed with a "good old faithful" like I was with one that had 180,000 miles on it and drove till 400,000 - went back to zero and still ran to 30,000 before I gave my older sister...and she rode if till she saved enough for her own and donated OR you can be soooo unlucky, like a close friend of mine who's first 3 cars left her in tears within a year. One started smoking to fire in the middle of a highway...next got transmitter issues, and the 3rd just stopped one day - and that was it! (well, at least by then she had credit to get a better car)
5) Drivers licenses: It is VERY HARD if you are coming in as a student, and IMPOSSIBLE if you are coming in as a visitor; but coming in on green card, you can have one anywhere as soon as you have your ss card, pp, proof of address, and a few bucks (like $26 - $42) - there is a list of acceptable items. Most states you go for computer test first (google DMV - then state where you intend to live to see what is needed). Most DMV's have their manuals posted on line so you can read for the computer test before you go. For some states - you qualify for road test within 10-15 days, others immediately, while others I hear you will need a temporary one first - and permanent one will be mailed to your house. Where I have been (2 states for me and 2 other states for spouse), it has been easy (all East Coast). I understand it is standard all over US that one must know how to do the "parallel parking" (I hear).
6) Jobs Search: I may sound proud here with the current economy but will state as it is. Most people/aliens believe that they must do shoddy jobs to survive the first few year...ok - I have no objection if that is what they want. Others believe that everyone must do NURSING or similar course to survive a better job - no problem with that idea either if that is what you want to do. BUT IF you already have a degree in something else, why waste it...a few courses can 'enhance it" to fit what American employers prefer. Not all American employers resent foreign education...you can still find a job. In my experience - I find going through Employment Agencies the easiest to land in a career job. You may end up starting up as a contractor but you'll still be making some money. Contracting HELPS - especially with learning the American culture, understanding American corporate politics/bureaucracy; and just knowing how to deal with people here. They may come in slots of 3 months for each employer but you get to learn so much, and you make better money than what you can at shoddy jobs. (If you are lucky - you can get at least $11 in shoddy jobs...some places $8 an hour. With contractor job of your career - count it from $17 an hour. If one has no degree/education, you can still get mailman job for $40,000 at an office (deliver mail, sort etc within the company), or secretary (for same amount) but only through contractor...and NOT with the state. LONG ANSWER! I can talk a lot!
A few more things about life:
1. For manual cars, most windows open the-other-wise compared to other countries.
2. Light switches turn on and off opposite of the other world
3. There are no PAVEMENTS - they call them SIDEWALKS here.
4. No car BOOT - it's TRUNK; and BONNET is called HOOD
5. Of course no PETROL - it's called GAS here
6. It is an insult here (a blessing in most parts of Africa) to tell someone "You look so good and fat"...the word "FAT" is considered an insult even when true. Unlike most places, in this place when you gain, people are concerned that you are stressed out. When you loose weight - "Oh, you look so good and happy"
7. Unlike most places (and I have lived in a few other continents), here people start announcing pregnancy even when only 3 weeks along...and not fully confirmed! Most other places "people notice that so and so is expecting"
8. Did I say that people date FOREVER, and get engaged to INFINITY before getting married and then start having kids at 38? (very normal here - uncommon other places I have lived but it happens)
9. Junk food is sooo cheap! Cake is $2.99 a pound or less; and Broccoli is $5.99! Beef is like $3.99 - 15.99/lb. Fruits/Vegetables are generally very pricey...but you can get the worst junk food for so cheap. They sell "organic" food...(I find that ironically untrue) for twice the price. There are a lot of canned/frozen foods!
10. Number 9 above has some grace added to it by the fact that we drive from garage to garage. With all the cheap junk, and no walking...it's easy to end up "looking stressed".
11. Google Dr. Oz, and see his research on Apple Juice....the most common juice around.
12. One more word - and I will start charging for reading...EVERYTHING here amounts to money! Very hard to earn, very easy to spend.