Okay, here's how far I am with what I'm trying to do.
I've added the following CSS:
/* My edits */
#content {
background-color:#00FF00;
width: 620px;
}
/* Make every instance of posts into a little box */
.hentry {
width: 300px;
margin-right: 10px;
margin-bottom: 10px;
float: left;
background-color:#9933FF;
height: 300px;
padding: 0px 0px 0px 0px;
}
.entry-title {
width: 300px;
background-color:#999999;
}
.entry-content {
visibility:hidden;
}
.entry-utility {
visibility:hidden;
}
.entry-meta {
visibility:hidden;
}
/*Special case for single posts pages */
.single #content {
width: auto;
}
.single .hentry {
width: auto;
margin 0px 0px 0px 0px;
float: none;
background-color:#FFCC99;
height:auto;
padding: 5px 5px 5px 5px;
margin: 0px 0px 0px 0px;
}
.single .entry-title {
width:auto;
background-color:transparent;
}
.single .entry-content {
visibility:visible;
}
.single .entry-utility {
visibility:visible;
}
.single .entry-meta {
visibility:visible;
}
/* Basic unordered post )page) with exceptions */
.page-template-template-fullpage-php .hentry {
width: auto;
margin 0px 0px 0px 0px;
float: none;
background-color:#FFCC99;
height:auto;
padding: 5px 5px 5px 5px;
margin: 0px 0px 0px 0px;
}
.page-template-template-fullpage-php .entry-title {
width:auto;
background-color:transparent;
}
.page-template-template-fullpage-php .entry-content {
visibility:visible;
}
.page-template-template-fullpage-php .entry-utility {
visibility:visible;
}
.page-template-template-fullpage-php .entry-meta {
visibility:visible;
}
/* Full page width template exceptions */
.page .hentry {
width: auto;
margin 0px 0px 0px 0px;
float: none;
background-color:#FFCC99;
height:auto;
padding: 5px 5px 5px 5px;
margin: 0px 0px 0px 0px;
}
.page .entry-title {
width:auto;
background-color:transparent;
}
.page .entry-content {
visibility:visible;
}
.page .entry-utility {
visibility:visible;
}
.page .entry-meta {
visibility:visible;
}
Now I just need to make the .hentry areas of all but those posts with exceptions (listed in the CSS above) have either a background image that's the post's featured image.