I was thinking the same thing. Avoid the shotgun approach, find the root problem and solve it. I don't think you did when you replaced the 1st alternator. It sounds like you got it solved with the 2nd alternator and the rewiring.
As for needing solar, if the batteries where fully charged to start and where getting charged each time you drove - you'd have had plenty of power for the camper and starting. I ran my camper for 3 days with the heater set pretty warm at night, lights, water pump, some inverter usage and had plenty of power to spare at the end without starting the truck once. Do you have a 12v fridge (that might push you into solar territory)?
Yes, I think I have the alternator problem fixed for sure now. I don't want to use the existing Surepower isolator I have because of the 1.0v drop across it. That means my truck batts would only ever see a max of ~13.5 volts. And the camper batteries maybe 13.1. Also, the Surepower isn't rated high enough. I'll get me a 1315-200, which will be good for some solar future (bi-directional).
Yes, my two ~650ah batteries were charged fully to start. But when I finally got the "lo-pwr" message, it was after the 5th night, running the furnace all night in 15 F temps (so sometimes running seemingly all night!) and some inverter usage, some incandescent lights, etc, propane fridge. And each day, driving maybe 2 miles max, on an alternator that was effectively dead. That's going to be a common occurrence for me (minus the dead alt). Although I'm going to get a Wave 3 and do LED upgrades before I do anything solar so maybe those upgrades will be sufficient and I won't run so low in the future. I do have two 650ah batteries for chrissake! They're like a hundred pounds of juice!