Ziffell,
As I read this, I can count at least four issues that require attention. There is really more wrong there than there is right. For years (before the depression of 09) I made a living diagnosing people's electrics remotely (often over marine VHF).
Let's start with the simple stuff.
1-Your converter is toast. That number is very old and even if it did still work, it has been so out-designed and it should be replace. Get a new 3 or 4 stage from Iota or Progressive Dynamics. If you have a single 12V, you can only use about 40 amps of charge at best so do not waste money on more.
2-You battery is done for. Even if you can get it to charge, why bother it will be a pain for all the future. If you plan to dry camp at all, see if you can fit a pair of golf cart batteries.
3-You have at least two bad connections in the system. You will have to find these and fix them, I cannot find them from here.
4-If your house battery is not shorted down (VERY DEAD), then your alternator is also in trouble (but this could be more bad connections). With the engine running, unless you combiner/isolator(or whatever) is dead, the battery should be over 14V for cold charging. Even a really old Mopar alternator should do that much.
Dealing with the noted should not be involved or expensive, but it should be done soon to contain the damage.
Good luck
Matt