If somebody owns a florist and they are the only employee, if they don't want to service a gay wedding, then the gay couple should move on to the next florist, somebody else will be more than happy to take their money.
Earlier I opined that might be a way to split the baby, but on second thought I don't see that as a solution for multiple reasons. State and local governments issue permits. If someone is to conduct business legally they have to abide by whatever conditions are tagged to that business licence/permit, whether it agrees with their religious preference or not.
But I still contend that permit issuing authorities and associated judiciaries owe it to the business community to convey clear and unambiguous rules on this issue, and if it's not clear now that time should be allowed for business owners to get their proverbial houses in order. The choices would end up 1) obey the law 2) sell the business or 3) shut the business down. Alternately, business owners can lobby legislative bodies to change law to their liking.