Things to consider:
Spring or fall? I don't think it makes much difference as far as seeing bears, that depends more on the weather and luck than anything else. But, any bear you kill in the fall will weigh more than that same bear would have in the spring. I've done both and I'd say I like fall better, but since I'm booked for this spring in New Brunswick I guess i Like both.
If you want the best pelt, go early in the spring. Be careful not to go TOO early as they may still be denned up, mid to later May is good.
If you want the best chance of a good scoring boar, go later in the spring when they are in rut and the big boys are cruising for sows.
If you want a chance for a color phase bear, you'll have go to Manitoba and west of there where they are common, they are very rare in the east.
Unless you really have a bug to go to Newfoundland, it's a long ways and expensive to get there. I'm going there this fall but we're going for moose. I wouldn't go to all that expense and trouble for a bear I could kill in Maine, NB, Quebec or Ontario for half the price and way less travel.