I have a 40 ton rt, grove 740b. Mid 1990's for age. Its really handy in a tight spot or for getting in a mudhole. You don't want to road it 10 miles. Its not legal because its too heavy for only two axles in my state. Some areas have a "commercial district" and can be legal to drive down the road.
The trans generally won't take it if you have hills, or with extended driving, they tend to heat up real bad. If you get any kind of speed up, they will hop on the tires. I try to get within at least a mile or so of the jobsite if I can. A lot of them don't have great brakes either.
My 700b series is only 10' wide, I think the 75s are 11', that makes it more difficult to trailer and haul around if you have narrow roads. Tail swing on the 75 is 14', so a narrow alley isn't much fun if there's trees/ walls/ buildings on each side.
I did not have a lowboy when I bought my rt, I bought a lowboy and trailer after about 9 months of having it hauled. Scheduling the hauling without my own truck/trailer was a pain.
I wouldn't have a RT as my primary crane in my rental business, its too much of a pain to move. But, as a option in the tool box, I do many jobs with my RT that I couldn't do without a RT.
I've looked at some 70-80 ton Rt's, and they are just too hard to haul around, because of their weight (80-90,000lbs), they require a long lowboy trailer with stinger, and 4 axle truck needed. I can haul mine with a 3axle truck and 3 axle trailer. So pay attention to what it weighs, because it makes a big difference in getting it hauled. Oversize permits are required from my state when I move mine. Not hard to get, it just adds up in price when you are moving it a lot.
If you like your tms300's, the rt's of that era are just more of the same. A great two speed winch, grossly overbuilt boom structure (which is a great safety margin in tree work) , same control layout so easy for guys to swap seats. If its been maintained, they are stone simple and pretty reliable.
They do tend to have short outrigger jacks, and the rt jacks start further off the ground with the big tires, which can be troublesome if its really crooked jobsite.
