How can I get the White Western Star back to the garage for the Fixer Upper task?

After much trial and error I finally completed this task, and since I know I'm not the only one struggling with it, I present to you my solution. Complete with freehand circles!

But first, let me just say that you shouldn't bother trying to go up with the hills. I know that seems to be the route everyone else is taking, but I also think that's why everyone is struggling so much with this task. I'm sure some folks can get up these hills no problem, but alas, I'm not that good of a hill trucker. If you're absolutely determined to use the hills for some reason, then wait until you've got access to a good Heavy Crane vehicle, since I've seen a few folks online saying that made the task easy.

Suggested route

I didn't have a heavy crane yet though, and since I'm confident I'm not the only one in that position, I suggest the following path which completely avoids the hills:

Instead of going up the hills, you drag it alongside the river, and then climb up the hill from the northern side. Once you're up there, you'll want to cut through the woods and down a hill, which will take you right next to the start of the "Find the Antenna Tower" task. Going downhill here might seem like a recipe for disaster, but it was actually really easy. The only tricky part that once you're at bottom of the hill, it's a tight turn to get back on the side, so be careful not to get stuck on a tree. Top of the hill is pictured below.

From here you'll want to proceed the River Crossing (1), which is right next to the "Lost Bags" task. This is probably the first tricky part of the route, simply because if you get stuck in the middle of the river, you likely won't be able to winch yourself out. I had no problem getting across, and I tried to mostly follow the drowned road (which you'll see labeled on the in-game map).

Once you're past the river, then you should have a fairly easy time until you get to the following location cliffside location (2):

This is far and away the most dangerous part of the route. It's a fairly narrow road, right alongside a cliff, with a tight turn. The other side of the road has some trees and boulders, if you get White Western Stuck here, the cliff might result in you having a hard time freeing it. So long as you drive carefully though, you should get through without issue. I'd strongly suggest having the White Western Star winched right up against you, since it should reduce the risk of it getting stuck or falling off the cliff.

After this cliff, though, the rest of the route is really easy, and you'll connect to the highway very soon. Congrats, you did it!

Cavaets

There are a few caveats to this route though. For starters, it's really muddy, so you'll need a truck that's comfortable in the mud. I did it using the International PayStar 5070 with All Terrain Tires, which you can purchase from the shop (it's expensive, but you should be able to afford it by selling some trucks, which you can always just rebuy later). Even with a good mud truck you might still get stuck in the mud a few times, but you should be able to get the White Western Star across by dragging it close to you with the winch, disconnecting, then advancing to some better ground and reconnecting the winch.

The other "gotcha" is that you'll actually need to complete a task to clear away from boulders just past the gas station. I can't remember the name of this quest, but it's a really easy task. All you need are two Spare Service Parts (I might have the name wrong), which you can get at the Service Hub next to the garage.

Finally, it's all but guaranteed you'll need to refuel during this route. I had to refuel twice with the Paystar, once before I took the hill shortcut near the "Find the Antenna Tower" task, and then again right after I crossed the river (1). I could probably have gotten by with just one refuel if I refueled right before the river crossing at (1), but better over fueled than stranded somewhere that's not easy for a refueling truck to reach.

Alternate Route

So with all that said, if you're not a fan of this route, there is on alternate route you could try as well. Instead of cutting down the hill near "Find the Antenna Tower" task, you instead keep driving straight, and cut through the swamp. I didn't take this route myself, but the folks online that were actually able to climb up the hills all seemed to take this route. There's no reason you couldn't still cut through the swamp but just skip the hill, and instead just cut alongside the river like I did. This swamp route seems waaaay longer than my route, but others have had success with it, so it's worth trying if you're not a fan of my route for some reason.