Election wise it looks a lot like OTL. McGovern performs similar to Humphrey; Goldwater performs somewhat differently to Nixon, weaker up North but stronger in the South and West.
Whoever you feel like winning, wins.
So in a fit of boredom, I've been playing around with excel and old election returns. Here's my best guess as to what happens: Goldwater by a nose. My simulated returns should be attached here as a JPEG; I can change the file type if necessary. I can't figure out how to post them in another way; I can PM the original excel file to anyone similarly bored.
Generally, I tried not to flip too many states. My first drafts actually kept showing a deadlocked Electoral College, but I think I underestimated Goldwater's strength in the South. The states Wallace wins here are hard to imagine him losing, given his margins, except for Louisiana, but there it hard to see either candidate picking up enough strength to beat him out.
I've let McGovern do a bit better, holding on to Minnesota and also taking South Dakota. He also takes Ohio and Missouri. The former seems logical; in hindsight, Missouri may swing more toward Goldwater, but New Jersey could also switch, going for McGovern rather than Goldwater.
Long story short, McGovern doing better in the North while Goldwater does better in the south (but not enough to dent Wallace's margins too much) is more likely to result in a deadlocked Electoral College than anything else. There are perhaps even more close states TTL than there were OTL. There were a couple scenarios were Goldwater only won with 270 votes so if a North Carolina elector is faithless, as happened in OTL, then the College is accidentally deadlocked!
If the election goes to the House, McGovern probably has an edge, assuming that the House elections are per OTL, but there may be some deadlocked states (Virginia, Illinois, and Oregon are kingmakers).
Also, I didn't take any native son effects of their potential VPs into account -- that could make or break the race.