Bangkok in five days, how to make the most of it?

Koh Phi Phi is about 900 km south of Bangkok, best advice if you only have 5 days is on arrival in Thailand fly directly to either Krabi or Phuket, recommend Thai Airways but many others which are discounted airlines offering lower prices but service not as great and baggage limits are low, your bag more for excess baggage then taken a Thai Airways flight. Take the boat to Phi PHi. Spend 3 days in Phi Phi then return to Bangkok and two days here. Many tour agents all over the city and at all major hotels, just ask. Recommend tours of the Grand Palace, maybe the Floating Market and Rose Garden tour. Get with a travel agent and look at all they have to offer.