Thanks for all the responses everyone!
I don't plan on having any rear mounted implements, so just the tractor and attached FEL is all I'm concerned with. But I know how things change.
Sounds like the 12' really limits me. I've considered resting the FEL bucket on the front rail or to load the tractor on backwards resting the FEL on the rear deck. That should be the lightest tongue weight with the engine and FEL on the back of the trailer, right? Or is this a no no?
Those are about my only options. Seems like a 14' might need to be considered and I'll just have to finesse it back into position in the shop after every time I use it. Or just park it outside. I know utility trailers are built to live outside, but I'm particular and try to take care of everything I own if possible. In the case I leave the trailer outside I'd just get a 16' or 18' trailer and have no worries. All things considered though, I'll probably use whatever trailer mostly for just hauling odds and ends and rarely use it to haul the tractor, but have it for the rare occasion the B2601 needs to go to the service shop or whatever. Family dreams are to own some more property one day and I might need to use a tractor there if we ever did find something.
I have a 1500 Sierra crew cab with 6.2L gas engine. It has plenty of pulling power, but the payload is a little light being a half ton truck. Manual says it can haul a 10,400 lb trailer with 1,100 lb tongue weight. I'm thinking the trailer, FEL, and tractor, even with loaded tires, would weigh less than 5,000. Probably closer to 4,000. I feel I could keep the tongue weight of a 5,000 lb 12' trailer around 500 lbs. (10% rule)