We have done that a few times .. when we get to our destination airport, we just find the package holiday rep, and advise them that we wont be using their transfer or hotel. It will just save them hanging about with a coach load waiting for you and your baggage.
Easy..!
Have a look at something like Travel Republic (www.travelrepublic.co.uk).
With them you may find the same or a very similar holiday but you can book (and only pay for) the bits you want (i.e. flight, hotels, transfers). Might be worth a try and you may save a few quid.