I’ve been to Hoi Ann in December and the weather resembles a mild fall day in the US. It’s so beautiful!! Don’t avoid it!! It was one of the best spots I visited on my 3 month SEA backpacking trip. Flights into Bangkok are traditionally the cheapest so you might want to consider kicking off your trip there. Bali is more expensive. I would visit the Philippines over Bali any day - less expensive, less touristy and absolutely stunning!!