Weight is a little vague, as it depends on a bunch of things - are the tires loaded, etc.
Also, manuals seem to have a good handle on weight of the tractor (4510 lbs), and weight of the loaded tires in various sizes, but the only figure I've found for hoe weight is "effective counterweight" (ie, what the hoe is equivalent to for the purposes of picking up a load in the loader), not what it actually weighs (quite a bit less) and the loader weight is never specified (that I can find). Maximum weight is 12,600lbs
The guy who hauled mine with loader, 13 foot hoe and unloaded tires guessed 7-8000 pounds by the way the truck went over the hills. For 16.9-28 tires, loading to the 75% point is supposed to be 750 lbs per tire.
Width varies purely as a function of tire and rim setup (axle is not adjustable). The 24 inch wheel is "standard" and can be adjusted (by playing with rim position) from 76-56" center-to center. The optional 16.9-28 tires (which both of mine happen to have) are fixed at 64" center to center. About 6 feet out to out, perhaps a few inches more. Not close to the computer to measure.
I've personally had no problems with the 3-cyl diesel. A lot depends on what the previous owners did. I've heard one claim I haven't verified here that the injector pump seal may fail and pump diesel into the lube oil - if the oil level rises, I'll worry about it. If anyone wants to chime in and confirm or deny now, that would be fine too. If someone ether-happy has been at the engine, bad things can happen to the pistons. The only problem I've had in 10 years with mine is a bad cable connection on the starter, and the fact that my thermostart is missing most of itself, I gather. That would be nice to have working. The cable from the generator to the proofmeter (tachometer) is often broken, and is easy to disconnect, so hours are generally unknown, or not reliably known.
I'm personally less than happy with the power steering set-up, but have gotten some ideas on ways around it, which I temporarily bypassed by getting a newer 4500 in somewhat less thrashed shape than my first one.
The main weak point on the hoe is the swing chains - and buying those from New Holland will scorch your wallet. I repaired one with grade 8 bolts as pin replacements (search back in 2000 or 2001, I think). You could move the ends over to a stock chain from an industrial supply for a lot less than NH wants, or even fab your own end plates to do that. On the up side, many parts still available from NH, though they often seem pricey to me. I guess I'm cheap. There, I looked up the old post in the archives.
http://www.ytmag.com/cgi-bin/viewit.cgi?bd=ford&th=37434