Right now I'm in Dallas, Texas and headed up to Portland, Oregon. My friggin' truck is starting to have an electrical issue. Headlights and the dash lights are flickerin' really bad. Either the alternator is going bad or my v-belt is shot. Either way, my mentor says to keep going until it dies because we have to get to Portland. I personally think we're not gonna make it before we break down.

I'll update later when we're sitting on the side of the damn road waiting for a repair truck.

Check the ground prong on the trailer connection at the trailer. Many times these get pinch shut and will cause a ground feedback into the other systems. You just take a small tip screwdriver or pocket knife (do not use your favorite) and slighltly spread the prongs. This has fixed the issue your or discussing for me many times. And also check the trailer pigtail on both ends to make sure it is completly in and locked.

Yeah, there is a real good chance the problem is in the trailer and not the truck if you are experiencing flickering.

Another possibility is to check the batteries and make sure all connections are tight.

I had a similar issue once....turned out to be the light switch in the dash....the wires got hot and fused all together at the switch.

Lots of scales between Dallas and Portland(say hello to Cabbage for me) but anyway, Unless you're just going to be running in the Daylight you're waving a flag to State Patrols and the Dot to pull you over
Curious what, if anything, you're putting down on your VI?
One thing leads to another and if you're not putting anything down your asking for a HUGE Log Book Falsification Ticket

We have one battery that we keep having to tighten the connection. When it gets even a little loose it really messes with things. That's what I was going to suggest. I guess it's a little late at this date but in case someone else wants the info.

Running with the kind of electrical problems the OP is talking about is a bad idea IMO. You can end up on the side of the road in a bad place. Better to pick your place than get yourself into a dangerous situation- say, heading up the hill into Oregon...

No load is worth putting yourself and/or others in danger. I know, I know- it ain't a perfect world. I'm just giving my opinion as to what I would do.

Darn good opinion if you ask me.

Turns out that some kind of control module was going bad and the connections going to the starter were loose.