Is there a liquior/grocery store within walking distance of the Downtown hotels where you can buy some beer?
There's a CVS on Ohio (about 5 block walk); they might have six-packs.
There's also a supermarket on Michigan & Senate, about 6 blocks north, if you consider that "walking distance." Of course, since the hotels tend to be north of the convention center as well, the distance would be shorter.
We are prepared to walk for hotel beer. :)
There is a speedway station just to the west of the CC. Beyond that, there are a lot of bars all over, and a few micro brewers that offer carry out jugs.
There's a Marsh Supermarket on N Senate Ave and W Michigan St. It's a few blocks away, but it's by far the best prices and selection nearest to the convention center proper.
The CVS as mentioned is close (near the Embassy Suites/Circle Center Mall), or you can get growlers at the Ram for sure.
http://www.marsh.net/departments/beers/
There's also a Crown Liquors at Ohio & Delaware - closer than Marsh, but I know nothing about them. :)
I've walked to the marsh and taken a taxi back, or walked back, in years past, depending on how much stuff I picked up. Also dropped my group and the luggage at the hotel and then drove to marsh myself one year. It is a good little market for convention supplies.
Big Red Liquors. 1/2 block North of Washington on Pennsylvania. Great place and even has delivery to the hotels and carries (well at least the past few years) the Official Gen Con beer.
Although it was better before Big Red bought it when it was called Kahn's Fine Wines.
Big Red liquors is a pretty good store close to downtown. Selection may be a little limited for major beer snobs. They do close somewhat early, I think I went there Firday in 2015 and they were closing at 11:00
The Speedway does not sell beer or liquor, just FYI. Indiana might be one of those states where only liquor stores and/or grocery stores can sell beer, or else the downtown Speedways just don't have liquor licenses.
I bought canadian whiskey at that Crown liquors on Ohio last February, it did not appear unsafe or anything to me, so I'd give you the green light there.
Buying before you go to the hotel seems to make more sense though, that way you don't have to either get the car out of parking or walk 5 blocks with an armful of alcohol.
Local Chiming in here on Indy laws,not an expert-but here is what I have run into.... Grocery's -are not allowed to sell anything chilled, so the cvs and marsh will have warm stuff. Also they wont have above a certain proof, no I dont know exactly what that # is. Liquor shops are allowed to sell stuff cold, so that is probibly your best bet, also they have more selection and higher proof hooch.
No sales on sunday, except at the bars where you can pick up a growler to go.
Also those with kids, no kids in the liquor shops or in resturaunts that don't have a sperate area for thier bar (basically if it says Bar or Pub-even if it's mostly a food establishment you can't take the kids in to eat).
Get a growler filled at Scottys or The RAM.