Don't feel bad, Lee, the thought of a home invasion scares the heck out of most of us.
While 00 Buck is the traditional default choice for the 12 gauge, I'm a little more inclined toward #1 buck. You've got about 100 grains more lead in the air for every pull of the trigger (the .30 caliber #1 pellets just fit more optimally in the 12-gauge shell's space, more lead and less air), with no really noticeable recoil difference. On a frontal shot, you'll often find 4 or so 00 pellets going through and through, but #1 buck seems to just about always stay in the offender's body. Better saturation pattern, too.
7.62X39 tends to be over-penetrative in most loadings. I would suggest swapping the Mini-30 you're already familiar with for the otherwise identical Ruger Mini-14 in .223, and loading it with 55 grain .223 hollow points. Lots of testing shows that most .223 rounds are less likely to exit a home structure than the .30 calibers,and no more likely to do so than most pistol bullets, and expanding bullet .223 loads have long been proven to be dynamic "stoppers" on unprotected targets.