Should I just lag bolt the ledger to the rim, or should I reinforce the rim joist with say a simpson strongtie htt4, and carriage bolt, and cut some cats to attach it? It seems that if there were a lot of people on the deck it could potentially rip the rim joist off the house.
What he meant by "load beams must be on posts" is self-explanatory. You may not simply use carriage bolts to attach your beam into the side of a post, like was done way back in the day. All the shear load would be carried by the bolts and eventually fail. Code requires that the beam rest ON THE POST, either right on top and secured with approved hardware (example Simpson post-to-beam), or notch the post and set the beam inside the notch, bolted to it.