Can you play Baldur's Gate without a mouse?
Solution 1:
From memory, there was a legion of keyboard shortcuts, but the only way to interact with objects was by mousing over and clicking them; I am 90% sure there was no way to "tab" between interactive items, and, for better or worse, Baldur's Gate was way before the current age of context sensitive controls.
Even if there was, you'd have to have a way to move your party/characters and control orientation of the formations of your party... I know it's Baldur's Gate, but it's probably more trouble than it's worth :P
You could buy a mini mouse, or go even further back to NetHack, or try out Dwarf Fortress.
Edit: Nowadays one can buy Baldur's Gate for iPad and Android tablets (and BGII for the iPad), which means you can play without a mouse.. just not on the PC versions we know and love ;)