I am taking a land/cruise tour 15 days

I am going to travel with 2 elderly clients who know that a China Tourist Visa is necessary for their trip in September. They cannot apply until 3 mos. prior, so around July I believe, right? We have the itinerary and cruise company is doing the air reservations and hotels, transfers and inter-country flights for this CRUISE TOUR.. How do we complete the Visa application without knowing the exact hotel, inter-country flights etc, as yet? We do know the planned arrival and departure cities and entire printed and planned itinerary. Can we mail the pertinent information rather than go iin-person to an embassy for the Visa if we have applied ONLINE?