This is the dress code for most of the signatures (copied from the official site)
Guest Policies
•Dress Code Guidelines:
Men: Khakis, slacks, jeans, dress shorts, collared shirts. Sport coats are optional.
Ladies: Capris, skirts, dresses, jeans, dress shorts.
Not permitted in dining room: Tank tops, swimwear, hats for gentleman, cut offs, or torn clothing. While T-shirts are now allowed, the policy remains that T-shirts with offensive language or graphics are not acceptable.
As you see, the dress code is quite casual and I certainly don't think it is onerous. No reason why your hubby can't throw a golf shirt and a dressier pair of shorts into his suitcase.