We were there last year for 4th July. We spent the day at Discovery Cove which was a perfect way to avoid the crowds, it was heaven. We then went on to MGM for the special fireworks in the evening. The park was packed to bursting but the atmosphere was great and the fireworks were fantastic.
MK has the special fireworks on the 3rd and 4th so we were able to catch them on the 3rd, again very impressive and worth the effort even though the park was packed.
I haven't heard of any special arrangements for travelling from offsite hotels, a lot of the shuttles do not run late enough for fireworks normally. I would budget for a cab.