Don calls home.

Sally takes a fall in her new riding boots.

Don comes home.

Betty gives in.

Don calls work.

Cooper writes Don a BIG check.

Don goes to work.

Trudy leaves Pete.

Peggy sleeps with the priest.

Joan pulls a Marilyn.

Duck dies driving drunk.

just theories...thoughts?

Those are all plausible.  Peggy banging the priest is a long shot.  Duck in an accident would keep Don from losing his job cause of the backdoor deal Duck made or Don could get a huge promotion upon returning.  I love theories, gimme more!

Betty gets Don's big check for the buyout, and promptly stashes it in her private account.

Don comes home.

Betty is pregnant, but she doesn't want to be.

Peggy comes to terms with her son.

Joan gets married, but catches her hubby-to-be in a compromising position before the wedding.

The company that buys SC fires Duck, despite his conditions when he brought them the deal.  Duck commits suicide.

Duck commits suicide... I saw this coming episodes before with the dismantlement of his family and the letting go of his prized dog. And as Cooper said "You can't trust the Brits."

I think Duck is in for a fall to be sure - he's on the bottle again (anyone catch him popping peppermint lifesavers before his big meeting with Roger and Bert?).  If he drinks too much in the wrong setting, it will be hard for SC not to mete out the same punishment to him that he insisted be applied to Freddie.

In some ways, Duck is the anti-Don, and either he or a character like him is a great addition to stimulate conflict.  Look where the two of them have butted heads this season - "the babies", dumping Mohawk for American, firing Freddie.  Each time, they've taken directly opposite positions and even though Duck's position has won out, nothing he championed has led to an improvement in his position at SC - quite the opposite.  But Don is still in place, still partner, still Duck's boss.

Duck sees the sale as a way to get out from under Don.  If the sale goes through, Duck wins, Don loses and it's a set-up for a power struggle between them in season 3.  On the other hand, if last season is anything to judge by, the resolution of each plot thread will come slam banging in on top of one another like a fifty car pile up on a foggy freeway, and the sale won't go though, and Duck will get the ax, thus clearing the decks for a new character next season.

Maybe.

"a 50 car pile up on a foggy freeway." (jkerouac59)

And I'm along for the ride. Better tighten my seat belt -- oops there's no seat belt in this 1962 model.

Enjoyed all your theories, so many possibilities. Here's what I think:

* Cold war tensions escalate and Don comes home to be with his kids and Betty (pregnant)--Is she or isn't she? only her hairdresser knows for sure (thanks, Miss Clairol).

*  Merger negotiations peter out due to the loss of the Clearasil account.

* A despondent Duck breaks out the case of Tangueray, over indulges and surpasses Freddy Rumson.

* Bert is relieved because he really didn't want to be put out to pasture with his Montana cows. He gives Pete a raise.

* Pete and Trudy separate and Pete moves into Don's old suite at the Roosevelt, which he can now afford.

* Peggy tells Fr. Gill his pitch is unconvincing and becomes a lapsed Catholic.

* In season 3 the Drapers will own a piano.

The piano is a very nice touch.

Not sure about the exact time frame of the last episode, but here's my take.

Don was unnerved by the nuclear strike "acceptable losses" pitch at the space seminar. On October 18, 1962, the Cuban Missile Crisis starts, and Don will rush home asap to be with his family if the Big One hits.

Great Britain, meanwhile, had control over several US Thor IRBMs that were stationed there. Trying to defuse the situation, they floated the idea of  immobilising them as a quid pro quo for removal of the Soviet missiles bound for Cuba. This was seen, after the fact, by some in the US as GB "chickening out" when push was coming to shove. Kennedy was not happy about GB taking this initative and undermining his position.
My guess is that it will raise the patriotic dander in Cooper, and he will see it as an opportunity to tell the Brits what they can do with their proposal. Duck, losing out, will hit the bottle big time.

Betty is pregnant, but will miscarry (too much horse riding?) and there will be enough guilt attached to drive her back into Don's arms.

I think Joan is also pregnant, and will stick with Dr. Controlfreak out of fear of raising a child alone. In those days, sometimes a bad marriage was better than no marriage.

At some point, Peggy will tell Pete that there is a child he can adopt. That will heal the rift with Trudy and her parents. The only question is, will Peggy do this for altruistic reasons, or will she get something out of it?

Roger's screwed in the divorce.

Somebody has to die while driving drunk.  I'm surprised MADD hasn't already started howling about this.  Don's car accident was not nearly enough.

Somebody has to die of emphysema, lung cancer or liver disease.  They mentioned someone dying of cancer at 51 in episode 12...not enough.

Somebody has to die in Viet Nam (see 'ya, Greg).

I think it would be great to do a dream sequence, fast-forward episode to about 1990.  Betty is a wrinkled hag with a horrible hacking cough, living on the stash from her second and third marriages, Don is institutionalized with multiple personality disorder brought on by too much acid in the late 60's -- their daughter is a crack addict in Newark and gives birth to a boy when she was still cute enough to be a hooker (sends Don to the institution for good); Pete is head of the biggest ad firm on Madison Avenue and gets indicted for insider trading with Ivan Boeski; Sal (this one is easy) died of AIDS in the 80's.  Etc.