Have been there twice for NYE - had to go a 2nd time b/c there was a downpour that lasted most of the evening the 1st time. Both times we spent the day at Epcot and got some of the major attractions (TT, M:S) done early before the crowds got really bad. We made ADR's for lunch and dinner b/c we saw people being turned away for TS restaurants without them.
Watching the fireworks from a restauant outside the park might be tricky - California Grill is always the best option for MK, but I imiagine for NYE that it's very popular. And there really isn't a restaurant outside Epcot that you have a good view of the fireworks. But if you eat early and walk the Boardwalk you can catch the higher fireworks from Epcot - but since a good portion of Illuminations is in the water, you miss that part of the show. But check for times for the fireworks b/c when we were there they had an early show around 7-7:30 for families with younger kids that wanted to get back to the resort.
We were lucky the first year - even though we went back to the resort, we were able to see the midnight fireworks from Epcot, MGM, and PI from our room at the Swan.