On flat ground, at low speeds, I wouldn't worry. I agree with the rest of your assessment. I have lost braking before with a load..I do know how that feels. Having it hauled is the way to go, but it's not worth it cost wise, even to just have it hauled over the mountain. There's always an element of the unknown in every trip, but just too much risk in this one. I once came over the hill with a drunk driver in my lane, and yes he hit me, another time on the same hill a guy thought he would pass without knowing if anyone would be in the oncoming lane, but I was there. Not sure how I missed him 3 cars on a 2 lane country road, had to have been inches, and he was flying. No use creating danger, there is enough out there already. I don't mind creating some inconvenience by going slow, but 30mph is going too slow the entire way. Add in bad weather...no way.

I was asking about the Adam's grader.  The 105 and 125 models were power controlled and had a single cylinder engine.  The Adam's 104 and 124 were the hand controlled models of that series.  I'm trying to find someone to get some info on the engine that was on the 105 and 125 because the one I am restoring is missing the motor.

I found an old post from six years ago. It’s saying that the 125 used a single cylinder Wisconsin engine no other info. Skinner 

It looked like a Wisconsin engine on this one too.

Curious how a pull grader would have been used on an steep incline? Especially with all the weight pushing the tow vehicle on the downhill, or the power required going uphill.

Have you considered putting the front of grader on a car trailer leaving the rear wheels rolling. That transfers weight to your truck and gives you more brakes. A lot of stuff was moved that way years ago not so much anymore. Just another thing to think about.

Road graders for the most part are not used on very steep inclines.
A simple explanation would be; Drop the blade going downhill to slow down and raise the blade to go uphill. Just how steep an incline are you talking about?

That could work, but I would need to deal with that 12' tongue. Getting it off is probably an ordeal. Plus I would still need to deal with those wheel bearings that aren't capable of speeds in excess of 30 mph.

Oregon has mountains, hills, canyons, and ravines wherever you look. I was just wondering how much of an incline they could be used on? The towing machines back then weren't that big as compared to more modern times.

Mountains, canyons, etc, are not unique to Oregon or any of the other states I have seen.
The question boils down to what were the intended uses and what was the towing power.

Size of the grader determined the required power to pull and control it.

Caterpillar Thirty's were used by many road departments for pulling graders, others used larger graders and Sixty's.
Both of these Caterpillars were heavily used in the timber and road construction industry as well as farming.

Years ago, pull graders were commonly used for "busting" rice checks. "Levee's" in some terminologies. These were often powered with D7 or TD18 tractors, the common power in the rice fields.

Some of the websites I listed in other portions of this forum may also show pictures of these machines.

CTS