Here is some stuff for your reading pleasure.
Yes, you put ice in an ice box...its a cooler and should have a drain to the outside.
As suggested , scroll thru here to find various projects and help threads:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/25966285.cfm12 volt side of life part 1 and 2 If you place a 12 v battery inside the camper, i would use an AGM battery because it gives off very little gas while discharging and charging and are recommended by the mfg.'s to be used inside.
AGM's also hold a charge longer while sitting idle.
If you choose to use a regular wet cell deep cycle grp. 27 or 29,31 then it should be installed in a vented battery compartment. Those gasses can be toxic.
* Remember, you should only run any battery down to about 50% of capcity for extended life of the battery. Use a volt meter to monitor the battery while at rest, not while you are drawing power from it.
I usually never let my batts drop below 12 volts while at rest. full charge is 12.6-12.8v .
TL rear tie-downs , hook up a rear set , designed to be secured to the truck frame. The following link has a video and pics of what you need. You then run a set of (spring loaded turnbuckles or fastguns )
pic of turnbuckle/fastgun as well as an anchor If you dont have a set of anchors built into the rear of the camper then you are going to have to fabricate a set. But they will need to be a solid metal fabrication "bolted" solid to the camper.
Look here at the pics of an anchor, wood rot camper repair to get an idea of what you need:
http://lanceowners.hoop.la/topic/broken-truck-camper Reason to use rear tiedowns:
If your camper has a cabover bed , then the camper can pitch forward while bouncing over bumps. As the rear of the camper lifts up off the trucks bed the front cabover tilts forward causing damage to the trucks cab as well as the campers cabover.
Good luck with the camper , dont be overwhelmed which is normal in the beginning. Take your time to read thru things.
Bob