take the 192 out of Melbourne all the way to Kissimmee keep on the 192 until you reach Avalon Road, turn right and go all the way to Winter Gardens were you join the West Orange Trail. Part of the Florida Connector.
Once you reach the outskirts of Kissimmee I would suggest using the side walk as the roads get really busy. There are hundreds of motels along this road, again I would suggest getting closer to Disney as the first ones you come to are not always very nice. If visiting the attraction choose one with free shuttle to the parks. Visit Celebration - amazing town and the restaurants are not the chain - take a ride round. I saw more wild life in Celebration than on my whole trip on the ST. You can go through Celebration and miss out a really bad part of the 192.
Also plenty of places to stay in Winter Gardens and good eating - take the W Orange Trail out, give me a wave or call in for a cuppa (I'm English) If you want more info let me know.
I would also suggest that from Winter Gardens you head on down by the trail to Oakland pick up the 50 all the way to the Withlacoochi Trail. One of my favourate trails.
Have fun it's agreat ride