I'm an optimist, but I don't think the Celtics will win every game. Tey won't be focused to win every game remaining, so it will be difficult to do so.
I guess they will win in Chicago and maybe Miami (their motivation against the Miami Hype Machine is not clear to me), win the last game at home vs. the New York Bricks, and probably loose one against Washington. They are playing them on back-to-back nights after playing Chicago and Miami.
3-2 or 4-1 isn't bad either. Probably 2nd seed, but being 3rd wouldn't be the end of the world. HCA is nice, but you can't have everything. The Celtics are waiting for the playoffs.
I'd love to be wrong, and I'll root for 5-0, but I don't think it's realistic.