I enjoy Opening Day and I think it was previously a tough ticket on first day of ticket sales. I am not sure if Opening Day is as difficult to get. But with the Theo-craze, you never know.

Pre-game activities/traditions such as morning activities in Wrigleyville on the 5th? - There are many, many bars in Wrigleyville and Opening Day starts early. A lot of new bars. Radio guys do their shows from some of the bars. Lately, I have opted for breakfast at Ann Sathers on Belmont or Uncommon Ground on Clark.

Post-game activities? - All those same bars.

We’re also attending the Saturday game, and since we haven’t been in the area in years, is there any decent lodging located near by?
- I don’t know of many hotels in the immediate area. I’d recommend staying down near Michigan Avenue and you can take the Red Line L to the game. On or near Michigan Avenue, you can get top flight hotels or a less expensive Best Western. And then your near all the downtown stuff to go see – Art Institute, Bill Goat Tavern (under Michigan Avenue), the Bean, etc.

A lot of information here. Not sure how up to date it all is, but a good place to start for general research.

Link

The Best Western Hawthorne Terrace on Broadway near Addison is about 4 blocks from Wrigley Field. The Days Inn at Clark and Diversey is about a mile away, but it’s a little cheaper 100/night. City Suites is on Belmont near Sheffield. You could stay downtown as long as you can get to a Red Line train. It's a short ride to the ballpark. Has anyone stayed at the Sheffield House, on Sheffield Ave two blocks north of the ballpark? It's an old rooming house (originally called the Hotel Carlos) that once housed a number of Cubs and Bears players in the 30s and 40s. I stayed there about ten years ago--$50. Our “neighbor” was a guy who imbibed so much he could hardly make it up the stairs at night. An interesting experience. But don’t bring your wife there.

…stag downtown. Priceline a hotel for $80 and there’s a good chance you’ll get something nice. Then it’s a quick 20 minute red line to wrigley.

Last year ESPN was broadcasting from the stretch, if that’s important to you.

I’d definitely get into wrigley in time for opening ceremonies. It’s always fun to see.

Anyways… before I moved to Chicago, I’d always stay at the Days Inn on Diversey when I came up for Cubs games. It’s probably your best bet if you’re looking to stay hear the ballpark. That said, having lived here for awhile now… I would suggest that you stay somewhere downtown and just take the red line. You can probably pay the same amount of money as you would at the Days Inn and stay somewhere much nicer.