There are a couple of random poorly worded questions I have about this point in the Pacific War. I'm specifically looking at the 3rd Marine Division
What type of boats/ships were the Marines on? I mean, were they with the Navy on a USS ship or did they have their own fleet of small or large ships? How exactly did they travel from island to island?
Once the island was secure, what did daily life look like on the island. What would a Marine's duty entail if he is not fighting.
Did Marine divisions act independently from one another, as in, was the 3rd division always in the same area/region as the 4th? or Would one be in Guam while another would be in Iwo Jima?
Thanks
There were a whole array of different types of ships that were used for transport of troops and material. These ranged from large Attack Transport ships to the more specialized LST's (Landing ship tank which allowed for beaching and unloading vehicles and personal for operations). Once an invasion was going to take place personnel would either go over the side into Higgins boats or go ashore in Amtracs. These were operated by US Navy personnel, although I know the Coast Guard was also used in these operations.
Training, rest, integrate the new Marine's into the unit and teach them how to survive in the jungle fighting environment.
It depended on the battle, at Saipan the 2nd and 4th Marine divisions were fighting, at Peleliu the 1st Marine division, Iwo Jima the 3rd, 4th and 5th Marine divisions. These division all fell under the Command of V Amphibious Corps. Other factors that could come into play here was how soon had they recently gotten out of battle and rest and reinforcements were needed to replace those killed and wounded.
DB2V2 has answered this adequately. There was a range of ships the US Marines deployed on, LSTs etc. There was a number of different landing craft from Higgins Boats to Landing Vehicle Tracked (LVTs aka Amtracks). They were all operated by the US Navy except for the LVTs which were organic to the Marine Corps' assault amphibian battalions.
It depends. Many of the islands were seized for their supposed strategic value as air fields to land bombers and the like, and staging bases. Of course, very controversially, some of the islands that were captured turned out to have no strategic value. Most controversially, Tarawa and Peleliu, which were bloody battles. As for what the Marines themselves would do, it depended. The Marines themselves would be training, resting and integrating new guys into their unit. After the Guadalcanal Campaign, I know the 1st Marine Division went to Melbourne, in Australia for several months of R&R while the US built up their forces. After the Cape Gloucester and Peleliu campaigns, they were sent to Pavavu (to their disappoint, it was an old coconut plantation and a hell hole with pest problems from rats to landcrabs)
Different Marine divisions would go where they were needed, and where they were able. Some campaigns had more than one Marine division (and often Army Infantry divisions).
The 1st Marine Division fought in Guadalcanal, Cape Gloucester, Peleliu and Okinawa.
The 2nd Marine Division fought in Guadalcanal, Tarawa, Saipan, and Tinian as a division. The 8th Marines fought in Okinawa.
The 3rd Marine Division fought at Bougainville, Guam and Iwo Jima.
The 4th Marine Division fought at Kwajalein, Saipan, Tinian and Iwo Jima.
The 5th Marine Division fought at Iwo Jima.
The 6th Marine Division fought at Okinawa.