Ruby on Rails

I'm kinda new to the RoR world and would appreciate if someone with the knowledge helped me out sorting some things.

I got a new project that I'm supposed to do but came up with some questions, it's basically a system to manage a Pub with basic funcionalities like inventory control, cash flow and client controls (probably with a bar code card).

Firstly we thought of doing it desktop based, in something like C# or Java, but came up with the idea of implementing it on a web based system. Then we came up with a couple questions:

1. The business couldn't rely on his ISP stability, as here we have really poor ISP, and the fact of the internet going down would probably ruin the entire night at the pub. The question would be: as if it were developed in Rails, what would be the praticability to run it in a local server primarily, but exporting it to a remote server everyday so it could also be accessed from home. I know it seems to go against some "laws" of web system developing, but would be quite the better solution for us. Or if there is any other ways to manage it locally, without entirely needing an internet connection, in the worst of the cases.

2. As it is a business, here in Brazil, we have now the option to print the customer's receipt for his IRS declarations. So the other question would be: if possible, how is this integration from RoR with periphericals, such as printers, would follow? Or if should it be done in anything else such as js. Honestly, I have no clues yet on how to do so.

Will appreciate any help given!

Thanks in advance,

Diego Dillenburg Bueno