The ride to Lauderdale from Orlando takes me 3.5 hours, and thats going 75 mph with no stops. Buses won't go that fast and I'm sure you'll stop.
People have been getting great deals for the Hyatt Pier 66, a very nice hotel here in Lauderdale, through Priceline.
I never take the transfers in Fort Lauderdale. If you stay at most of the hotels, the port is very close and very accessible. A cab doesn't cost that much. The bus, you have to wait for and it may be crowded. With a cab, you can hop in and go to the port when you want to.
We have stayed at the Westin (the one a bit outside Fort Lauderdale) and the MArriott Harbour Beach, both through Priceline. They were great hotels!