2013 Tacoma- Blown Main Alternator Fuse

About a week ago we had a dead battery. The tow truck driver that AAA sent out tried to jump it, but reversed the cables and blew the main 140A alternator fuse (and a few other fuses). We had it towed to a local dealership that wasn't able to replace the fuse that day but soldered it back together just so we could get on our way (we are traveling out west). I've been looking for the replacment fuse and had a dealer a few hours away order one that should arrive next week. In the meantime, I explored the fuse box to see if it was realistic for me to replace the fuse myself rather than pay for the couple hours of labor to disassemble the fuse box and remove the bolts that hold the fuse in. It seemed doable enough, but when I reattached the few wires I disconnected and reconnected the battery, the truck wouldn't start. I undid and redid everything I had done. That included loosening one of the fuse bolts, pushing the fuse in to make sure it was connected and then retightening the bolt. Lo and behold, the truck started! But when I turned it off about ten or fifteen minutes later and turned it back on, it wouldn't start. We took a look at the fuses and found that the soldered main alternator fuse had blown again (the solder was burned through leaving a visible gap).

So here's my question: any idea why the fuse blew when the truck started? Just the current frying the solder, because it was just solder and therefore not a permanent fix? We are not near a dealership and don't have another vehicle so may need to solder the fuse again just to get the truck running long enough to get to a dealership that has the replacement fuse, but I don't want to do that if it's possible that there's something amiss with the circuit that would put the electrical systems of the vehicle at jeopardy. Do we solder it again, or just pay to have it towed hundreds of miles to the nearest dealership that has the correct fuse? Any help or advice is appreciated!

 

Hundreds of miles round trip or one way?

Personally I'd rather have a professional assess things. Towing the vehicle a long way is still probably cheaper (especially with AAA) than accidentally frying your ECU.

 

160 miles one way to the dealership that will have the part next week. Might be another dealership about 50 miles away that could have it; will know more about that tomorrow.