OK guys.
The safe bet is the leisure centre. Always full of away fans, never any bother. Can't miss it - it's fairly huge and at the top of the hill smack behind the away end.
There are some pretty safe pubs in town as well, though so you're not completely stuck. I've got a Leicester fan mate who currently lives in Newcastle coming down and I'll be dragging him for a prematch pint. The trick in town centres is knowing where's safe and where isn't before you venture in. Avoid the Groggers Rest and the Court House near the train station but the Gatehouse is fine. You can then gauge the atmosphere and see whether a head into town is a good idea. However, away colours and light hearted banter will not be allowed in the chain pubs (Yates's, Wetherspoons, Walkabout etc) - they tend to be a bit paranoid. However, they'll have bouncers and not usually be full of arseholes, so as long as you cover up and don't get lary you shouldn't have much bother.
I would stay out of the Mount near the ground - shit beer, too full, occasionally raucous clientelle. The Dove Inn at the top of Oakwell lane has only just reopened after a refurb. Nice pint but an unknown quantity - I've not really seen any away fans in there. The Outpost on Sheffield Road is also reputed to be friendly towards away fans albeit a fair hike from the ground but for this reason I don't bother with it.