We are all glad to help, I'm sure. Speaking for myself as a long time mechanic and repair shop owner I am still trying to figure out just how to make internet help effective. So help me too....
Just so you know, most dealers make quick estimates based on the cost for parts then double that to cover the labor. With that in mind, $2500 for a clutch job is not far off. Depends on what they find.
And keep in mind that some mechanics just naturally replace anything at all worn when they are in a tractor that deep, whereas others only fix what is wrong.
In the past, I don't think that I've spent enough time just asking these initial questions to get a feel for the owner's abilities and the tractor. Some photos along with a history of the tractor would sure help too
So what can you tell me about your mechanical abilities? Tools? Shop...Do you enjoy mechanical projects? You are going to need a flat floor space longer than the tractor, a Harbor Freight crane ($200), and a dolly stout enough to gently roll half the tractor away from the other half. And a clutch plate lineup tool.
Oh, almost forgot.... do you have a workshop manual for specs, and a parts book so you can post pages here on TBY so we can all point to the same part?
Luck,
rScotty